moonh

Your width is sent at 940px

#access .menu-header, div.menu, #colophon, #branding, #main, #wrapper {
    margin: 0 auto;
    width: 940px;
}

make that smaller to what you want, also your banner width is 940 so first work on making the image size smaller.

Your header also has 30px padding so shrink that to 0px if you don’t want any gap or around 10px for a small sized one.