Thanks again Jeannie for the wonderful advice. We are moving along very well with this little girl. I took her for two little walks yesterday (on her own as I wasn't sure how she was on leash) and she enjoyed it a lot. I can tell she is still a little nervous from not being outside for such a long time, but she was eager to go the second time.
I also got the two of them playing with toys simultaneously yesterday. She is starting to perk up a lot and even trying to play with Wallee. He, on the other hand is not really ready to physically interact with her but that's ok. I also notice that when he doesn't like something she is doing, it is more of a grumbly growl than anything so I am just leaving it be. I know they have to figure out who is in charge so until I see him actually do something that I think is aggressive, I will let him teach her the rules. (hehehe..although sometimes I even have to remind him that he is "not" the referee of the cat's play fighting).
Today I am hoping that we will see a little sunshine and am going to try to walk them together. I am still having some potty issues with her which I expected and feeding is a whole other ball game. They said that they were cooking her chicken and rice and mixing in her kibble...well, I have tried the same thing and she picks the kibble out and leaves it on the floor. I don't mind to cook for her, but just chicken and rice is not good. So, now to try to get her eating some dog food.