columns are not even

joomla 1.5.23, php 5.3, mysql 5.1

I am using the parameters plugin, and have three columns defined, each with width of 180...however the display shows the middle is smaller, and the right one is too close...

www.gertrudezachary.com

where to edit to correct this, cannot make effective change in plugin!

changed column widths to 120, but the columns are displayed at different widths and looks amateur...
Where to edit and make this look like a menu that costs way too much too implement and takes up way too much time to seek out the mysterious and hidden files to edit.