I for one, welcome our new decaying overlords.
Seriously though, (to the extent such a question allows anyway), I'd send in the National Guard. It's kinda their job to deal with this sort of stuff, and they've got guns and tanks, which tend to be pretty effective against zombies.
Either that, or go in single handedly, because I'd have to be one of those action presidents, you know, like John Kennedy or Teddy Roosevelt.