I see Joe got here with the copyright advice before I did.
Your photos are automatically copyrighted as soon as you shoot them. You don't have to do anything. But it might be a good idea to run a copyright notice right across the middle of each photo until you receive payment. (As a warning to unscrupulous folk that you're up on the legalities.)
AND...since the photos have attracted some attention, it might also be wise to register them. I think you can register a whole series at a time, to avoid paying a fee for each one. You'll need to see a copyright attorney about that. (Look under Patent, Trademark or Copyright Attorneys and ask for a free initial consultation.) An attorney can also advise you about standard contract terms for selling photography.
OH!
I almost forgot...
GOOD JOB, girl! I am not one bit surprised that someone outside of A2K has noticed your talent. I'm just happy it's someone with money!
