Adjust the width in the following accordingly. Do your maths. 🙂
Right Column: template.css (line 561)
#ja-col2 {
float:right;
overflow:hidden;
width:22%;
}
Left Column: template.css (line 552)
#ja-col1 {
float:left;
overflow:hidden;
width:28%;
}
Left Colum + Content: template.css (line 511)
#ja-mainbody {
float:left;
width:78%;
}
Content: template.css (line 518)
#ja-content {
background:transparent url(../images/content-center.gif) repeat-y scroll center center;
clear:both;
display:block;
float:right;
width:72%;
}
you also need to make changes to the images used for background of the contents so that they can fit accordingly