ok, life might be easier if you did convert that to a better codec for editing.
BUT...
if all you need to do is a simple cut down, maybe re-shuffle some shots, and export,
you can work with what you've got.
last time i got the red render for audio was when i was working with some DV Stream footage.
all i was doing was removing shots and trimming.
what i did was to render the audio of the whole clip in the timeline before i started trimming.
then FCP let me work quite freely.
unlike picture renders, i could trim and re-extend the audio without having to re-render it.
if you want to maybe grade and add effects,
then i think you would be better off converting before you edit.
use compressor to convert your footage to ProRes, or ProRes LT.
cheers,
nick