I would definately check with the vet too! See if its a med problem first.
If you see her pee on the floor, dont punish her. This is called positive punishment. What she learns is not that going potty on the floor is bad, but going potty in front of YOU is bad. She will become confused. Therefore, she may become sneaky and pee places where you dont see her, or not pee when you are watching her (like when she is outside and you are with her). It may not have happened yet, but it could start. Negative punishment is like when a puppy bites you and you ignore it and leave the room, the puppy learns biting is bad. The punishment is directly linked to the behavior and is clear and direct. You are removing the stimulus that caused the behavior, where as with positive punishment you are adding an aversive stimulus, which can cause fear and confusion for dogs and not solve the behavior problem but actually make it worse or develop it to something different. I know it sounds confusing... sorry.
What I would do is the second you see her pee in front of you, pick her up(even midpee, they will sometimes stop and hold it) put a leash on her and take her out. Dont say anything, just do it. Take some treats and walk around with her, saying "go potty Reba" walk her till she goes. If you caught her mid pee, she should go again soon. When she does, YEY act like she just won the lottery. Treats and lots of praise. Then take her inside and keep her on the leash and close to you. If she tries to go again, repeat. But chances are, if she is leashed to you, she wont go. Keep up this routine and develop a command for going potty. Soon she will learn going outside is what she needs to be doing. I hope this helps!!
I think once she completely understands you she will start responding better, but until she is going outside on command consistently, crate her or have her with you when she is in the house. I dont think it will take too long! Be patient, she's a smart girl and she'll figure it out!