Go to the
AKC website and click on Events and Award Search. In the menu click on your state, select "conformation events" and specify the time frame for the past 12 months it will show you a list of all of the shows in NC. You can click on each show, scroll down to the Toy group and click on the hyperlink--this opens up all of the breeds in the group. Click on Yorkshire Terriers from there and you can see all of the dogs entered there.
I would look up the kennel names on each one and do an investigation. You can also post here about lines you have questions about. Once you find a line you are interested in go and meet that breeder at a show or at their home. I would focus on building a reputation with them before you start really talking about a dog.
Another thing you might want to consider is talking to some of the well known handlers. You are still going to have to build that repoire with them but they may have access to lines that the individual consumer wouldnt necessarily.
Best of luck again!