How to put the menu above the content?
#block-system-main-menu {
   float: left;
    top: 0;
    width: 100%;
}
#block-system-main-menu ul.menu
{
float: left; width: 100%;
}
#block-system-main-menu ul.menu li
{
float: left; width: 15%;
}


Use this css.it will help you

Simply put Your menu block above main page content block in same region and that menu will show above the rendered content or other option can be to change the order of the regions in the page.tpl.php file in your theme.