Hi welcome to YT. please read as much as you can on getting a new puppy. It sounds like you will be getting your puppy at 8 weeks old and that is NOT recommended at all. Good breeders will not allow their puppies to leave their homes until they are at least 12 weeks old.
check out these links before you purchase your puppy:
Yorkshire Terrier Club of America - yorkie club site full of great information about the yorkie
http://www.yorkietalk.com/forums/fea...ead-first.html