While fiddling with Sibelius 6 at school I noticed it had a plugin that could generate drum tracks based on bass and guitar tracks. They didn't sound bad, and I was wondering if Guitar Pro 6 had something similar, either vanilla or by plugin. It may suffice until we can get ourselves an actual drummer.
We're a metal band, by the way, and the song in question is 180 bpm and very reminiscent of Iron Maiden's style.