I always recommend the YTCA breeder referral, especially to people who can offer a good home. Right now their site isn't working, but here it is for future use.
http://www.ytca.org/breeder1a.html Most of the breeders on the list are breeding to improve the breed and dogs that aren’t suitable for breeding for whatever small reason are placed in pet only homes. They make perfectly good pets, but just have a minor flaw that might keep them out of the ring. Older dogs that have been held back are also a great bargain, because the price often drops as a dog gets to be 6 or 8 months of age, and sometimes their only flaw is that they are too small to breed. Good breeders are always looking for good homes to place their pet yorkies and since you’ve proven to be a good and experienced Yorkie mom, you’ll have no problem passing their tests. If you find a breeder you really mesh well with, I'd ask to be placed on their list, some breeders won't do a breeding until they have pet homes available.