Floated Layout - Overflow Problem

Im currently suffering from a problem where a png images’ height exceeds the floated div it sits in. This is fine in firefox as it displays it correctly, it simply overlays the png ontop of the div below it.

In IE7 it displays the image behind the div below it regardless of the z-index I give each div. And in IE6 it pushes the whole floated layout down to accomodate the image! Not ideal at all.

Here is my site, and if you view it in each browser you will see what I mean more clearly. Any advice on how I can get the image for the logo to sit above my banner would be appreciated.


Cheers Guys