Here is a chart from Kimberly's site (feminvstr) just click on the link below. By all accounts it seems to be very accurate. My pup is 2.7 lbs at 4 1/2 months and I thought he was small, next to yours he is positively monstrous!!!!!! Good luck with your puppy and welcome to YT.
http://yorkiepassion.com/growthchart.htm
Sorry, I thought you wanted to know how big puppy was going to get, not when they are fully grown. But good info on Kim's site anyway.