Quick CSS Layout Change Job

I need someone who understands CSS to do a quick layout change for me on a Wordpress theme. The theme currently has standard header, content, sidebar and footer areas. The sidebar currently sits under the header which runs the full width of the content.

What I need is for someone to make the necessary changes to the CSS file so that the sidebar starts at the top of the page so the layout looks like the attached file.

No other changes are required and I am hoping that it will not be necessary to change any of the code on the WP pages, only within the CSS file.

Have include page.php and thestylesheet in the attached zip file.