Here - easy to prove that AKC does Not register "yorkie-poos." See any on this list 
http://www.akc.org/breeds/complete_breed_list.cfm
? Sorry no. It is a mixed breed. It is easy to do your reseach - you just have to look in AKC web site. I did even try to do a search on AKC site for yorkiepoo, yorkipoo, yorkie-poo. And I got nothing. If they actually were recognizing them - the search should have pulled up something. Sorry. Could it have been another registry?
T.