Hi Kara,
I think it's wonderful that you're asking questions...Typically, the pups should not leave their mothers and littermates until they are twelve weeks old...Even though they are already weaned earlier than this, it is important that they get this socialization time. They learn alot from the mother and littermates.
Just so you know, there is no such thing as a teacup yorkie. There is only one kind of yorkie, and that's a toy yorkie. Yes, there are some smaller ones, and yes there are some larger ones, but as far as classification by the AKC, there are only toy yorkies. Small or large, they're all yorkies
I hope that the mom is not a "teacup" because if she is under 4-5 lbs, she really should not have been bred...It's very dangerous, and her life could be on the line when it comes to giving birth to the pups.
As far as the pups go, I'm sure you're super excited!! I know I was whenever we were getting our yorkie. They're such wonderful babies. Please don't hesitate to ask any questions!!