best of luck in whatever you decide to do - I was suggesting involving the shelter that recommend her to you so that there is a third party there to assist in talking sense into the lady that has her, and that can address the state of the home and check on the other pup you saw there that you have concerns for.
if you decide in the end that you cannot keep her, and need her to go to a stable, safe, healthy home, then please consider posting here for a member to take her in for you. there are lots of helpful, loving yorkie people here that want nothing more than a happy ending for you and your pup.
__________________  billie ralphie sophie  maddy boo sadie ben |