Page width trouble

Hi,

Iv’e managed to set up my site almost the way I want it, but I’m struggling with a width issue. As I don’t want the sidebar on either the forum or schedule page I managed to set up a separate template page called forum.php. Now I want to wider the content container for them two pages so both the forum and schedule fill their pages.

Ive tried messing with the style.css file but its very sensitive to change as the sidebar on the homepage miss aligns.

How Do I extend the forum and schedule to fill up the page without disrupting the homepage? Do I need to set up a seperate .css file?

I can post the .css file if needed, Im using the handsup79 theme. You can find my website here http://www.radiokitchensync.com

Cheers;
Sean