Lol. The Mbox interface is the pre-amp. The pre's are built-in.
You can't half-ass drum recordings. Period. Getting a good recorded drum sound is not eay to do. Also, sticking 2 mic's on a snare is a nice luxury to have, but by no means is it necessary. If you can't get a decent sound with one mic, adding another will most likely blow your mind.
Bottom line - you have to experiment. Minute changes yield different results. Mic positioning, angle, distance, etc all plays a part in finding the sound you want. Listen to the vast variety of recorded snare sounds out there on CD's and stuff. They're all different. First thing you do is learn how to tune a snare and get it sounding how you like it. The diamter, depth, shell type, and heads all play a role in how it's gonna sound. Get whatever you have sounding the best you can. Then once you have that, you can start the tedious process of finding the sweet-spot for the mic. You must experiment. Only you can find the right combination of snare sound and mic placement. We can't tell you what to do. If this is too much for you, go buy a drum machine.