Responsive design?

Hey, I have re-designed the face of my site. I have a menu bar embedded in the background as this is how it worked best. It looks perfect on my 13" Mac screen but have realised on a bigger screen it doesn't sit in place. I checked to have the responsive design in a hope that it would work but it's still the same problem. Boo My site is http://wwww.thelostlondoner.com Do you have any ideas? Is there some hidden code that keeps everything the same despite the size of the screen its being viewed on? Otherwise I may have to scrap my custom menu bar and go back to using the sites generic one. Any help is greatly appreciated. Picture of how it looks on my 13" mac http://www.flickr.com/photos/92334073@N06/10800058725/ Picture of how it looks on a screen larger than 13" http://www.flickr.com/photos/92334073@N06/10800073685/