You can change the content.css file to have the width be 100% under the OuterWrapper css block.#outerWrapper {
margin: 0 auto 0 auto;
text-align: left;
width: 760px;
}
to:
#outerWrapper {
margin: 0 auto 0 auto;
text-align: left;
width: 100%;
}
You will have to modify some other look and feel attributes too however, since the pages are built for 760px width.