Hej, Alex.
I was able to override that sidebar area by going directly into the grid_view.css file and changing the width of the #grid_view_products_page_container div. (In my case, I was trying to get rid of the sidebar area on the main products page.)
I think what you’re looking for is the #single_product_page_container div, whose width is specified in the wpsc-default.css file.
Beautiful site, by the way.
Held og lykke,
April
