Check site formatting at all resolutions/ all browsers etc

My website [login to view URL] has started "showing up with the column on the left hand side as being down at the bottom of the page - below the text in the main column. Could be my hi resolution on my laptop but it looks very ordinary. Also the whole site only occupies 50% of my screen. Either way it needs to be optimised for hi-res." I want the site fixed to look good at all resolutions/ all browsers by someone who knows exactly how to do this. Thanks.