[songpony]

I utlitized an external USB sound device which boosted my volume a fair amount (and at about $80 was well worth it - it also eliminated the hum and other noise I was getting on the 1/8" headphone jack). Also, if you're using a mixer, turn up the gain on the channel the computer is on (or some will have a push-button on the channel to "boost" it a little) - this will also increase the music volume without impacting your mics.