do you have any sequecing software, like ableton, cuebase?
if so, record your mix to audacity as a big WAV file - Save in folder -
open this up in your sequencer, get the volumes / eq going good then burn down to an MP3 of your chosen quality
if you dont have a sequencer im sure you can just make a huge mp3 in audacity when you 'Export' it??
i now use adobe audition to record mine, had loads of problems with audacity for some reason. Auditions cool it gives you a big waveform and level meters as you're recording so you can check levels then lets you normalise and amplify/reduce and generally fuck about with the recording once youve finished the mix, plus it lets you save as .wav or mp3 or whatever you want without other software
Thats the new cool edit isnt it? That was one of my fav. pieces of software, so simple! All about ableton for me tho now when it comes to editing. Cool edit is a little destructive for my liking.