mm perhaps give this one a try make your header in png format and rename it as your header.gif or whatever format your header is right now and overwrite it. I am not sure will it work or not but giving a try is worth it.
I would suggest correcting your html and then perhaps the page will render the way it's meant to render. All that extra css, and then the incorrect css, and then the meta tags not in the <head>. You have 581 errors on that page and 4 warnings.