laptop audio - quiet and "hissy"

[songpony]

I recently started using Hoster. I'm running it on a brand new HP laptop and in general, everything is great. However, I'm finding that my overall volume is limited by the laptop's audio output; I'm using the headphone jack, as that's the only audio out on it. I've got the mixer channel the laptop is on pretty well maxed, while my mics and laserdisk player have LOTS of headroom. I've got the volume up on the computer, and I upped the volume of the "quieter" disks when I loaded them, but I'm still really pushing it. When I increase the volume for that channel on the mixer in order to get the music at the right volume, I start getting a hissing or "staticky" noise - it only occurs when Hoster is actually playing (if I have the channel up that far but the song is stopped, there's no noise, so that tells me it's only occurring because of the audio output). Does anyone have any suggestions for either of these two problems? The stereo channel I'm using on my mixer doesn't have an actual gain control - just two settings of -10db or +4db (I have it on the +4, which is the loudest). I've been told to try using the line input on one of the mic channels (which does have a gain), so I'll be trying that tonight to see if that helps the volume issue - don't know what to do about the hiss (or if this will even help with the volume). Anyone else experience the same thing? Thanks.