That's sad that she was like that. I think she had a good owner if she was that friendly and calm around people. You should find a way to post something in Houston (or where ever you found her) I'm sure her family misses her.
As for you, I know it will be hard to let her go, and from the way you make it sound, it makes me sad you can't keep herBut giving her back will probably make some family very happy. When I lost my dog, I was hysterical. I am so happy the people called me.
I have a chihuahua, and somehow he got on the other side of town and followed some first grader home(he loves kids) But I couldn't have been happier when they called. I was crying before, but when they called I cried even harder because I was happy.