How to change specfic table borders

I have the lasttest Topic script in the top of my page with difrent forum cats ect.
As you can see on my picture below, i want to change the two tables:
"Tilbud fra sponsorer" and "køb-salg-bytte" tables, so they fit more into the page and not are so width.
I have tryed everything, but now am lost and cant find out where specific to change it.

Link to the picture in full size:
http://www.malleforum.dk/Lastest.Topics.table.width.jpg