Welcome to YT! I also took in someone else's dogs, although they did not have nearly the dangerous situation your new little angel has gone thru. I would recommend spending as much time with her as possible. The more hours you can spend with her, the quicker she will adjust to you and warm up to her new home. If you leave a room and she does not follow. Take her with and sit her down in that room and encourage her to explore.
Love, reassurance and consistency are very important. Trust yourself.
This is a great place to learn so much about Yorkies
Yorkiesmiles