You could look on this site for breeders and for a lot of information about yorkies and their general care. I would suggest starting by finding a great breeder. There are some breeder questions that you can find in the search option on this site (or even find breeders from YT).
I know it helped me to figure out how much I was
at the most willing to pay. You also may want to look for breeders in your area by looking in the local paper or google ______ (city) puppies for sale and that should bring up a few places that have dogs that are publicized.
Please please take a moment and investigate where you get your dog from and their home. I got caught up in puppy wonderland with my shih tzu and he has severe socialization issues that I am still working with almost 2 years later.
Best of luck
Oh btw, I was so also adament about getting a small yorkie (one that would be under 4lbs full grown) and then I learned from this site about how much care goes into keeping that small pup safe. I have a projected 5.5lbs little boy and a project 4-5lb girl and they fit in my purse fine.