I would look in your local newspaper and look at
www.breeders.net. Make a list of breeders that you want to contact and start out by visiting several. You want a breeder who has puppies that are well socialized and preferrably raised in the house and not in a kennel. Make sure the living conditions in which the puppy has been raised are clean and sanitary. You also want to see BOTH parents. Don't trust a breeder who will not let you see BOTH parents AND the living conditions of the puppy. You will get your best estimate on how big a yorkie will be based on the parents. Don't trust a breeder who uses the word "teacup."