What excuses have you been given? Sometimes there are legitimate reasons why they don't have AKC registration for you right now, but if the excuses keep changing, it sounds like something is amiss. If you know the parents of your Yorkie, I believe you can call the AKC along with your breeder information and see what is going on. Eight months is WAY too long though in my opinion. We got our AKC papers right after we got Yoda. If the AKC registration is important to you, I would set a deadline for your breeder to give you the papers, if not, either file a claim through small claims court or get a lawyer. And never do business with that person if she doesn't deliver the papers before the deadline.
Good luck, and oh yeah, WELCOME to our Yorkie community!