Head shot from senior portrait is perfect size. It should NOT be a glamour shot. They want to be able to recognize you when you walk in the door. The business cards are a cute idea but not appropriate for this purpose. Also a 4 x 6 snapshot is fine. You may also end up emailing them so be sure you have an electronic copy.
Thanks so much! I love the cards, but I want to make the best impression. I'm sure I can use them for tons of other things. Again, thanks for your help.