It sounds like you are doing the very best you can with the unplanned pregnancy. I wish you well with a safe whelping -- and wanted to let you know that many of us will be sitting in the maternity waiting room when the time comes and will be glad to offer what help and advice we can.
You have already been given some fantastic advice by Kalina82 and SET Yorkies. It would be fantastic if you could find an experienced Yorkie breeder (or small dog breeder) near you that would be willing to be on call.