I thought I wanted a Yorkie too, until I researched them for several months. They have too many health problems for my needs (luxating patellas (bad kneecaps), they need a lot of dental care or need their teeth brushed a lot, there are problems with liver shunts in the breed, they have problems with hypoglycemia. Of course, all Yorkies don't have all these problems, but they are common to the breed. But the biggest reason I decided not to get one is because they are hard to house break, often times taking a year to totally house break. I am a very good dog trainer, but I couldn't put up with a dog peeing in my house for a year. I would love to have a Yorkie. I think they are the cutest little dogs ever, plus I would love the lap dog aspect of owning one. But after reading about and researching them for months, I decided they are not the breed for me.
This Yorkie forum is very informative. YorkieTalk.com You might want to join it, and learn about the breed before buying one.