Blocks placed "Below content" have a narrow (right-column) width...

I've been trying to post a block in the "Below content" area. Unfortunately the size is about the width of the right column -- even when I put something large (large amount of text, an image, a table) in the block. I'm currently trying to put in a table (2x2) which looks fine in a Blog or Page, but when I stick it in a block below content it doesn't work. (You can see it here: http://www.askgriff.com/node/19)

Thanks in advance!

Robert Griffith