The easiest way to implement it, would be "over" what we have, so to do so each button etc would need to be an individual item.
I could probably do it in html with frames and ****, but Im not 100% on CSS, so will leave it to Bells.
But as I said, if each part is an individual item and roughly the same size of what its replacing on the site allready, it shouldnt be too much of a hassle