[Resolvido] layout com no ie7, e ruim no FF

oi gente, estou faze esse layout a critério de estudo!

eu gostaria que ele ficasse assim assim:

/applications/core/interface/imageproxy/imageproxy.php?img=http://img337.imageshack.us/img337/388/layoutcm9.th.jpg&key=88e4cacccfbf3b2f0dbf26460380d6e158a4bcd5ade32742649d7c33521c03d3" alt="Imagem Postada" />

eu acho que já até consegui montar ele no ie7, mas no firefox, ficou uma porcaria! :(

para você visualizar como ficou, clica aqui

o meu css, está aqui:

BODY { margin:0 auto; background-color:#FFFFFF; align: center; }div#corpo {background-color:#FFFFFF;width: 770px;margin: 0px auto;table-layout:fixed;float:left;font-family:Arial 11px;}div#logo { width: 770px; height: 130px; display: block; background: url(imagens/site/topo.gif) no-repeat right top transparent; background-color: #FFFFFF;}div#novidade { width: 200px; height: auto; background-color: #FFFFFF; margin-top: -437px; margin-right: 5px; margin-left: 5px; padding-top:0px; border-right: 5px #0060B6 solid;}div#conteudo { margin-top: 0; margin-right: 0px; margin-bottom: 0px; text-align: left; vertical-align: top; float: left; padding-left:215px; padding-top:0px; } div#rodape {width:auto;height:40px;width: 770px;color:#CCCCCC;font-family:Arial, Helvetica, sans-serif 10px;background-color:#000000;border-top:#0060B6 solid 4px;}ul.nav { margin:0; padding:0; } ul.nav li { list-style:none; display:inline;; }ul.nav li a { float:left; border-bottom:3px solid #0060B6; height:20px; width:110px; font:12px Arial; font-weight:bold; background-color:#000000; color:#FFFFFF; text-align:center; text-decoration:none; padding-bottom:1px; }ul.nav a:hover{ background-color:#000000; color:#FFFFFF; border-color:#FF7F00; }ul.nav2 { margin:0; padding:0; } ul.nav2 li { list-style:none; display:inline;; }ul.nav2 li a { float:left; border-bottom:1px dashed #000000; width:200px; font:12px Arial; color:#0060B6; text-align:left; text-decoration:none; padding-top: 2px; padding-bottom: 5px; }ul.nav2 a:hover{ background-color:#F0F8FF; color:#0060B6; border-color:#000000; }p.conteudo_negrito {font-family:Arial, Helvetica, sans-serif;font-size: 12px;margin:0px;padding:0px;color:#0060B6;font-weight: bold;width: 100%;}p.conteudo {font-family:Arial, Helvetica, sans-serif;font-size: 11px;border-bottom: 1px dashed #0060B6;margin:0px;padding:0px;padding-bottom:1px;width: 100%;}p.conteudo_coluna {float:left;font-family:Arial, Helvetica, sans-serif;font-size: 11px;border-bottom: 1px dashed #0060B6;margin:0px;padding:0px;padding-bottom:1px;padding-right: 2px;width: 183px;padding-top:5px;margin: 0px auto;margin-left:2px;border-right: 1px #0060B6 solid;}a_site:link {font-family:Arial, Helvetica, sans-serif;font-size: 12px;font-weight:bold;margin:0px;padding:0px;padding-bottom:1px;text-decoration:none;color: #000000;}a_site:visited {font-family:Arial, Helvetica, sans-serif;font-size: 12px;font-weight:bold;margin:0px;padding:0px;padding-bottom:1px;text-decoration:none;color: #0060B6;}a_site:hover {font-family:Arial, Helvetica, sans-serif;font-size: 12px;font-weight:bold;margin:0px;padding:0px;padding-bottom:1px;text-decoration:underline;color:#FF7F00;}