Trial and error worked. I figured out that to widen the boxes i needed to edit the width in here:

.progressmeter li {float:left; width:10em; min-height:3em; margin:0 .6em; padding-left:3em; color:#000; background:#b9cfe7 url(../images/numbers.gif) 0 4px no-repeat; list-style-type:none;}

Getting there :)