Change Layout to Ecommerce page, CSS, PHP

HI I have a page that isn't converting very well. I sketched a rough layout and had a designer created the elements for the redesign the existing page is : platinumplates.co.uk/private-number-plates-buynow-D10+ASW its dynamically driven from the databases, my hand sketched new layout is attached. Currently when you select "buy now" there are selections revealed lower down the page. The new layout should on click of buy now button, the options should be revealed over the top of the current page like a sand box type option over lay. Similar to when you select the warrenty options on this page: [login to view URL] There are several different variations of the button like BUy now, Proceed, Continue etc the testing environment should be able to swap the buttons and we we decide on which one we can name it the same as the existing button so it still works, if there is anything else needed to know we=hen I change the button, then you need to tell me. With the current option the nominee details are only captured when the certificate radio button is selected, I need this information captured and sent to me in both certificate and assignment options. The buyer has to check the box to agree to purchase before they can proceed to the payment pages, this still needs to be the case in the new layout.