error.php page custom configuration question

Hey guys,

just created the 404 page for my website:
http://kinogrill.kz/404

was wondering on how to remove the left sidebar with menu,chiken,socialicons from the page? to leave only the main menu, logo on the top, content, footer. To have everything but the left sidebar

What should i change in my error.php page or should the changes be done in the article itself?