Welcome to the site and glad you found us, and bless you for taking her in. That poor girl has been shuffled around too many homes. I wish you could just keep her. She needs to be on a better food and that will help her with most of her problems. She looks fine from the pic and doesn't look over weight, but a better food will help her. Here is one thing you need to do to really help her. Have her spayed before the people want her back. Tell them she got an infection and needed the spaying.
What a great idea, David...yes, please spay her and say she had infection!
I join the rest in thanking you for taking her in, GOD bless your kind heart