You can start with the Yorkshire Terrier of America website at
www.ytca.org There is a breeder referral there. YOu may even be able to find someone in your area. If they don't have something available they may know someone who does. Just remember, you may have to wait. I am just in the process of placing a female pup to new owners that are friends of mine and they have been waiting since spring for a female.
I will caution you that females are not easy to find. There often not as many born as males it seems and a show breeder will tend to run those females on to see if they are show quality to keep for their breeding program. Anything that is sold for pet has nothing wrong with it, it just isn't what they want for the show rings and therefore will let if go to a pet home spay/neuter contracts. They should be AKC registered if being sold as purebred and will be sold with Limited Registration.
If you do plan on flying somewhere to get a puppy, plan to spend a day or two to get a feel for the breeder you are talking to.
Puppies should never be less than 12 weeks of age at the time of sale. I also never let my puppies go to a new home if they are less than about 2 1/2 lbs. There can be too many problems with ones that are younger than 12 weeks and less than 2 1/2 lbs.
A health guarantee for genetic problems should be at minimum 2 years, 5 is better. Genetic problems don't always show up in the first year. A general health guarantee for one year is fine. Sometimes the contract will stipulate what is and isn't included in that guarantee.
I can't help you if you want a crossbreed such as a Yorkiepoo. Just remember this is not a breed and there could be anything in the parentage behind the pup. Which is fine but sizes will often vary even if the parents are small. I have seen two 5 lbs parents produce a 25 lb Maltese/poodle cross.
Lorraine
Loriben Yorkies