
Heather a Yorkie bred to the breed standard will be pretty small. I am assuming you are not looking for an unhealty tiny one, just not one of the ones that are the size of a Cairn or Westie bred by people who have not even read a breed standard :D
If you contact the breed club/s then you will be able to register your interest with a responsible knowledgeable breeder for a typical puppy.
If you go to the Kennle Club Website click on breed standards, then toy Group, then on the breed, read the standard, and then at the bottom you will find a list of breed club contacts.