Stop, come up for air, and do what should have been done first: set some long-term goals for where you want your credit to be, figure how you're going to get there, and then write it down.
I don't know what your other two cards are, but if the Best Buy is the store card rather than the MC, you now have a store card with a good limit, an account with Citi, an auto loan, and whatever else. This is a great base to work from. See how what you have fits into the long-term picture, and take care of the stuff you have now.
* Credit is a wonderful servant, but a terrible master. * Who's the boss --you or your credit?
FICO's: EQ 781 - TU 793 - EX 779 (from PSECU) - Done credit hunting; having fun with credit gardening. - EQ 590 on 5/14/2007