**sigh**
I did it! I like that the Apple Store gives you the chance to use two cards towards a purchase. I couldn't take out the full amount from checking, but I saved myself a lot of interest by putting as much as I could there first. I can pay off the rest of it in 3 months (very conservatively), by my calculations. I also can afford the $15 upgrade in AT&T charges ($15 instead of $20 because I'm paying an extra $5 per month for 200 text messages as it is) since I just paid off my car.
My girlfriend is going to KILL me!