Hi,
The DIV that wraps the column, class=col1, specifies the width of that content.
I would create a new class with the width you want for the page and add the appropriate style to you styles.css file.
For example, in styles.css
.col-full {
width: 930px;
}
And in your template, change the line
<div class="col1">
to
<div class="col-full">