drive to one of the nearest larger cities and go to some shows/concerts. and not shows that you know will end up being total bro-fests, either, but ones with bands that girls tend to enjoy (usually groups of the more "indie" variety).
i don't know how close you are to san francisco, but if you would be willing to drive, go to this show:
RILO KILEY: 6/18/05 - Grand Ballroom, San Francisco
seriously. i absolutely guarantee you will find at least a few cute girls at this show without any guys in tow. of course, who knows how old they'll be, so make sure to pay attention to the drinking wristbands. plus, after a few drinks, chances are strong they'll be more open to having a conversation with a stranger. even if you don't like rilo kiley, just go. if someone asks if you like the band (which would be kind of a dumb question, since the general assumption should be that you do, in fact, like the band, considering you are attending their show), just say that you are unfamiliar with them, but a friend told you they are good, so you thought you'd check it out.
of course, if you aren't really into music in general, or it's just too much of a drive, then it's probably not going to work.