Header Iframe – External page

Hello everyone!
I’m trying to build a new site, swapping from Joomla to WordPress.
I’m getting some troubles, couse I want insert an iframed page on my site.

The site should looks like that (sorry for the bad quality of the images)

http://www.spacemonkeys.it/images/ifvpa/1.JPG
http://www.spacemonkeys.it/images/ifvpa/2.JPG

But atm looks in this way
http://www.fvpa.it/wordpress/test/

As you can see, the right block reduce the iframe section.
I need to make it wide than now.
Thanks for your helps!!

[ Please do not bump, that’s not permitted here. ]