Oh, that's right... I guess I could have my own Q3Mon then.
My issue was that I tried to compile GameTrakker-3.6 (it integrates MRTG and QStat) and couldn't get through all the errors. It's a nice package that provides usage graphs, averages, and everything. Hasn't been maintained, though

EDIT: here's example of GameTrakker results:
http://bohramt.de/GameTrakker/