Editing category listing view on Coppermine

Hey,

I posted about this on the Coppermine forums but no one seemed to really know (or no one responded who did). I would like to make the front page category listings two columns wide instead of the default 1 category, it's albums, then the next, underneath of it, i.e if I had 10 categories it would be a 2x5, like so:

cat cat
cat cat
cat cat
cat cat
cat cat

Instead of the default:
cat
cat
cat
cat
etc.

I've been editing theme.php and other files and have gotten the album listings the way I want them, but I can't seem to find the right spot to edit the category listings like how I want them. My site is http://www.wallpapernexus.com/index.php

Thanks for any help!