It looks like that theme does not have a template without a sidebar. So you would need to create a custom template — see this:
http://codex.wordpress.org/Stepping_Into_Templates
It would mean removing the sidebar car code and then modifying the CSS code so the layout is adjusted accordingly.
If you’d rather alter it from page to page, there are plug-ins that will do that for you – search the plug-ins page for dynamic sidebars.
You can likely find a plug-in to do the header as well.
Thanks, I’ve tried the plug in for a dynamic sidebar, but it hasn’t done anything, perhaps I chose poorly? Do you have a plug in you would suggest?