Karen, that is so heartbreaking someone would treat the little girl like that. God Bless you for bringing her in and giving her the medical attention and loving home that she needs. I imagine she had 3 years of an emotional life, and has been with you for 1 week, I am sure in that 1 week you've made a huge difference to her but it could take a few months for her to let go of her past and feel completly at home with you.
Good luck to you and the little yorkie girl. I hope some one on the site will be able to give you great advice, all I can offer is a hug.. hugs to you and your little yorkie girl.
p.s. did you give her a name?