Hi,
I've made those changes as can be seen on the site now but I think the css may be grouping the header and the main body meaning when I change background-color: #fffff to #transparent it makes the whole lot transparent.

#headerWrapper, #contentMainWrapper, #logoWrapper, #cartBoxListWrapper, #ezPageBoxList, #cartBoxListWrapper ul, #ezPageBoxList ul, #mainWrapper, #popupAdditionalImage, #popupImage {
background-color: #ffffff;
margin: 0em;
padding: 0em;
}
.topper-menu li {
font: 11px verdana;
float: left;
margin: 9px 2px 0 14px;
}

It also leaves two bands of white around the banner.