Twenty Eleven – make page (default template) full width

Hi

I’m new to wordpress and have used WP-tables reloaded plugin to create a table. I’ve placed this table on a page (default template)in my test blog at
http://www.rathmullancottages.com/blog/page-test/

How do I make the table wider as I can only seem to get it to occupy a relatively narrow central section of the page. I’d like the table to be almost full width

ps – it appears full width if I choose the showcase template but there is a grey background and related posts below (which I don’t want)

Hoping someone can help with this

Regards
Brian