banner / logo as a full width background

header currently has this:

<!--header start here-->
        	<div id="header">
            	<!--logo start here-->
                <div id="banner"><img src="http://www.quicksalehouses.co.uk/wp-content/themes/twentyten/images/banner.png" alt="banner" /></div>
                <!-- <div class="site-url"><a href="http://www.quicksalehouses.co.uk/" > www.quicksalehouses.co.uk</a></div>  -->
                <!--logo end here-->

              <div class="clear"></div>
                <div class="menu">
                	<ul>
               <li class="<?php if(is_home()){ echo "current_page_item"; }else{ echo "home_link"; }?>"><a class="" href="<?php echo get_home_url()?> ">Home</a></li>
               <?php wp_list_pages('title_li='); ?>
                   </ul>
                    <div class="clear"></div>

                </div>

            </div>

        <!--header end here-->