Definitely advertise now if you can! But, if you don't take posession of the new home until July, how are you going to conduct interviews? If it is near enough that they can come to your current daycare for the interview and you can show them what it will be like, that would maybe work, but if not, then you may be stuck not interviewing until you move. In which case, I probably wouldn't advertise until a few weeks before and say interviews start on X date. Good luck!