header, as in header/footer type terminology? don't say header.. it gets confused with heading tags and head tags. fyi only - no offense... have you tried going about it a different way like this? : position the band absolutely against the header from the top and left like so: top: 450px; left:0px; margin: auto; padding: 0px;
or this: put both the header and the band in a containing div tag. position them inside the div tag relatively or absolutely, then float the whole div.
also, you have one div tag and 2 closing div tags.... you may think your using some css that your not actually using. fix those. let me know how it goes..i will try and help u further.