Small Magento job - move columns down 450 pixels on front page

We want to make som small changes to our website silverinvest.no. On front page we will have banners in full width at the top, and then three columns under this. See test here: [login to view URL] So you probably need to insert an area at the top where we can insert banners, or somehow say that left and right column should start about 450 pixels from the top of the page. Also let me know how/where to change the size of this "banner area", if we need to adjust it later. //Feel free to set project in another category/"skill search" if its not posted the correct way.