Welcome to YT! There are others here would have Yorkies and cats that co-exist well. I think the biggest mistake people make is thinking that they will adopt any breed and it will all work right away. We have a Boxer who is 6 years older than our Yorkie and eventhough she is the sweetest girl ever it was still a transition for everyone involved. Good luck!
PS You came to the right place for all things "Yorkie"