Hope you did not get stuck with one of those lame Grad Cards sold by the school and Yearbook company. You know, the ones without photos, the fake silver foil that peels off and cheezy 1950's design.
There is STILL time to get a custom card designed, printed and in the mail within a couple days for under $2 each. Buy one card or 100, all printed, stuffed, addressed and mailed for you. The fun part is you can included a baby shot or two on the inside of the card to make it a true keepsake. Something they keep and don't toss in the trash after a quick boring look. Plus if they send you cash for graduation you can use the same program for thank you notes.
You will send thank you notes, won't you??