Use webmaster mode and
Firebug to do this.
Left side bar's width can be added by edit the css file and you will editing #left-bar, .fancycat-page-subskin-c #left-bar
Code:
#left-bar, .fancycat-page-subskin-c #left-bar {
margin-left: 29px;
top: 29px;
width: 250px; /*Change this*/
}