How to Alter Blogger Template

This is my first attempt to alter my blogger template, I thought I would want I discover.

Increase over width of page:
/* Wrapper */

#outer-wrapper {
margin: 0 auto;
border: 0;
width: 1200px;
text-align: $startSide;
background: $mainBgColor url(http://www.blogblog.com/moto_son/innerwrap.gif) top $endSide repeat-y;
font: $bodyFont;
}

Previous value width: 692px;