What are you thinking of anyway????????? You trying to kill that female Yorkie??????? Breeding her on her first heat is totally irresponsible!!!!!! I don't know why people don't do their studies on dogs and breeding before undertaking such an expensive and dangerous undertaking. Get her spayed and him neutered.
Please read this:
http://www.itb.it/canaan/icdca/Breeder./facts.htm