[Lynne]

You have a custom style which is why the regular options don't work.

You have these widths which needs to be modified:
#mainwrapper {
margin: auto;
width: 906px;
}
and this
.doc_header {
height: 220px;
margin: auto;
position: relative;
width: 1000px;
}
and this:
.navbar {
background: url("styles/af/misc/skin/") repeat scroll 0 0 transparent;
border: 0 none;
border-radius: 0 0 0 0;
clear: both;
color: #FFFFFF;
font: bold 11px Tahoma,Arial,Calibri,Verdana,Geneva,sans-serif;
height: 90px;
margin: 0 auto;
position: relative;
top: auto;
width: 932px;
}

Those are all in the MDstyle.css file (or template, I don't know which).