If you're only going with two, I would recommend getting some kind of pencil condenser mic as your one overhead. The SM57 is OK, but it mostly excels as a close-up mic, like if you were to mic your snare only. If you want to capture the entire kit nicely, a condenser would be the way to go. When I use two mics on my kit, I have a SM58 that I stick about two inches inside my bass drum port, and an AKG SE300B as my pencil condenser overhead and it sounds great.
I would almost recommend going cheaper on your bass drum mic and getting a good condenser, especially since your budget is so low. Like I said, a simple Shure SM58 in the bass drum doesn't sound that bad. You could save $100 on that alone, and then you'd have two mics you could use for everything.
BUt you haven't said what you're plugging into. I'm guessing some kind of computer interface? Make sure that's good too - the mic is only as good as the pre-amp its plugged into. Good luck!