How exciting! Puppies can be a lot of work, but they are so rewarding. Make sure to post lots and lots of pictures when you get him/her! Everyone has their own oppinions about how to raise and train their dogs, so you will get lots of different ideas about any question you ask. Don't let this overwhelm you or take away from your excitment about the new pup. Just listen to it all and then take whatever ideas sound best to you.
Here's what I personally would put on my pre-puppy shopping list:
* Crate - I think the big crate with divider is the way to go. There are two reasons: 1, you'll save money by not having to buy another crate later (your pup will grow quickly, expect about 3lbs a week), and 2, because of the divider you will be able to adjust the size better as the pup grows (they need to have enough room to lay down and walk around a little, but not so much that the pup could pee in one corner and sleep in another).
*Bowls - eventually you'll need big bowls (most people go elevated too), but for now you only need small ones on the ground. I would go get one of those cheap plastic double feeders. I wouldn't spend a lot of money on it since you will be switching to bigger and higher ones fairly soon.
*Buckle collar - get a small adjustable collar that is thick enough to be comfortable on a big dog. Make sure it is nice and sturdy, but save your money and don't bother buying a fancy decorated one, because the pup will outgrow it soon.
*Leashes - I like the regular nylon leashes, but you may like retractable ones better. Whatever you decide to get, I would suggest getting a spare so that you don't have to worry about your only one getting chewed or peed on by the pup, and also in case one gets misplaced you won't have to go searching through the house just to take the pup out.
*ID tag - once you actually get the pup you'll have to get a rabies vaccination tag and dog liscence for the dog to wear, but you will also want one of the normal id tags that has your address and phone number in case the pup ever gets lost. You can get one of the instant-engraved ones at petsmart, but I have tried them and they flake off and become useless very quickly. I prefer the plastic ones you send away for because they cost the same but last so much longer. I suggest ordering one once you have decided on a name (whether thats before or after the pet comes) because they take a week or two to come in the mail.
*Beds/bedding - I would suggest getting something soft for the pup to lay on, especially if you have hard floors in your house. But like jacksmom I suggest you stick to something cheap for now because the pup will end up ruining whatever you get with accidents or chewing. Also, I highly suggest giving the breeder a blanket to put in with the litter for a few days before you take the pup. The scent will be very comforting to your pup on those first scary lonely nights at your house.
*Sour apple spray - sour apple spray is harmless, colorless, and odorless, but most dogs hate the taste of it. Buy a bottle and spray it on whatever you think your pup is likely to try chewing but don't want them to chew.
*Disinfectant and carpet cleaner - It's pretty much inevitable that your pup will have accidents. Be prepared to clean and disinfect, and don't use an ammonia-based product (the smell will remind the pup of pee and make it want to pee in that spot again). I personally like clorox bleach wipes for wood floors and petastic for carpets (it was previously sold as natures miracle, but now the formula people think of as nature's miracle is sold as petastic and nm is a different forumla). I also like 'resolve spot magic' for tough stains. And buy lots of paper towels.
* Poop bags - if you plan to use plastic grocery bags, start collecting them now. I personally prefer to buy the ones that come in pocket packs because I never have enough useable grocery bags and hate having to always check them for holes first.
*Treats - for training you will need tiny treats that the pup can eat quickly. I would suggest soft ones, because I found that zoey would take forever to eat the hard ones with her baby teeth, which made them bad for training. I used little tiny jerky squares and also the biljac soft treats (zoes LOVED those). Bits of cut up fruit/veggies also work for some people. You'll also want a little container (a ziplock bag work fine) that you can keep in your pocket for potty trips.
*Toys - if your dog is busy chewing on a toy, he won't be chewing on your clothing/furniture/etc. Get a wide variety to keep it interesting for the pup. Just keep an eye on the pup when they are eating anything that they can break off a peice and swallow (ie stuffed animals or rawhides). I would suggest you stay away from greenies which are made predominantly of wax and easily swallowed. Zoey's favorite chew toys were soft rubber squeekera and bully sticks.
*A brush - a simple cheap brush is fine for now. You just want to get in the habit of brushing the pup regularly. This will not only keep his fur nice, but it is also a great bonding activity. When you brush the pup, gently touch all over, including paws, ears etc. It is good to get the pup used ot being touched now, because if they grow up thinking that being handles is a positive thing, it will make vet visits and grooming much easier later.
*Ear cleaner and dog toothbrush- getting the pup used to having their ears and teeth cleaned from a young age will make it easier to do once they are big enough to struggle with you if they don't like it.
*Shampoo - your pup will probably get into all sorts of messes and will need to be bathed. If your pup is like my Zoey, who managed to get into a smelly messes constantly so that we had to bathe her practically every other day, you will need conditioner too so you don't dry out their skin.
*Food - eventually, what food to feed will be a big decision for you. But for now, it has already been decided. Buy a big bag of whatever the breeder is already feeding, and then you have until the bag is almost empty to decide what you want to do. Whatever you choose, make sure that you gradually change the food - switch about 10% a day.
*A good vet - since you already have a cat, I assume you already have a vet that you like. Make an appointment with them for a new puppy check up. They will check the pups health (should be good since you're getting it from a groomer, but you never know for 100% sure). They will also answer any questions you have and put you at ease about any concerns. Mine also gave me a big goodie bag full of pamphlets and samples for new pet owners.
*Baby gates - you probably have some already from your children, but if not, go get some sturdy ones. They are really important for keeping dogs in the rooms where you want them.
That should pretty much cover you for your new arrival.
Oh, and one more necessity: a digital camera to post pictures on BPO