Changing width of center page

[treasureshaven]

It is easy to change the width of both side columns but I just cant seem to find where to change the size of the middle of the page.
Looking at my webpage here
http://www.meteoriteshop.com/
I have a flash video that I want to run in the middle between the two side columns but it is to large stay in the middle. How do I increase the middle?
Thanks

[kobra]

Find your stylesheet for this template and try the following

#mainWrapper {
	background-color: #383E44;
	text-align: left;
	width: 980px;
	vertical-align: top;
	border: 1px solid #9a9a9a;
	}