I've been searching for free software to clean up live audio too. I post a lot of videos on YouTube, when I see bands live, and I would love to be able to clean up the audio.
I haven't really found anything yet. I use a Mac.
Sometimes it just is what it is. In order to make any sort of real difference you'd need something on the order of ProTools audio sculpting. Then what are you left with? Processed garbage. Stripped of soul.
Sometimes a cheesy Polaroid photo can be charming beyond words.