How to move the last to float right of the menu?

/* menus::base */
div#menus {
    height:41px;
    background:url(images/main-bg.png) center repeat-x;
}

div#menus ul {
    margin: 0;
    padding: 0;
    list-style: none;
    float: left;
}
div#menus ul.menus {
    padding-left: 0px;
}

div#menus li {
    position: relative;
    z-index: 9;
    margin: 0;
    padding: 0 5px 0 0;
    display: block;
    float: left;
}
div#menus li:hover>ul {
    left: -2px;
}

div#menus a {
    position: relative;
    z-index: 10;
    height: 41px;
    display: block;
    float: left;
    line-height: 41px;
    text-decoration: none;
    font: normal 12px Trebuchet MS;
}
div#menus a:hover, div#menus a:hover span { color: #fff; }
div#menus li.current a {}

div#menus span
{
    display: block;
    cursor: pointer;
    background-repeat: no-repeat;
    background-position: 95% 0;
}
div#menus ul ul a.parent span {
    background-position:95% 8px;
    background-image: url(images/item-pointer.gif);
}
div#menus ul ul a.parent:hover span {
    background-image: url(images/item-pointer-mover.gif);
}

/* menus::level1 */
div#menus a {
    padding: 0 10px 0 10px;
    line-height: 30px;
    color: #e5e5e5;
}
div#menus span {
    margin-top: 5px;}
    /**@replace#1*/
div#menus li { background: url(images/main-delimiter.png) 98% 4px no-repeat; }
div#menus li.last { background: none;margin-left:260px;}

/* menus::level2 */
div#menus ul ul li { background: none; z-index: 9;}
div#menus ul ul {
    position: absolute;
    top: 38px;
    left: -999em;
    width: 163px;
    padding: 5px 0 0 0;
    background: rgb(4,57,123);
    margin-top:1px;
    z-index: 9;
}
div#menus ul ul a {
    padding: 0 0 0 15px;
    height: auto;
    float: none;
    line-height: 24px;
    color: rgb(169,169,169);
    z-index: 9;
}
div#menus ul ul span {
    margin-top: 0;
    padding-right: 15px;
    _padding-right: 20px;
    color: rgb(169,169,169);
    z-index: 9;
}
div#menus ul ul a:hover span {
    color: #fff;
}
div#menus ul ul li.last { background: none; z-index: 9;margin-left:260px;}
div#menus ul ul li {
    width: 100%;
    z-index: 9;
}

/* menus::level3 */
div#menus ul ul ul {
    padding: 0;
    margin: -38px 0 0 163px !important;
    margin-left:172px;
    z-index: 9;
}

/* colors */
div#menus ul ul ul { background: rgb(4,67,142);z-index: 9; }
div#menus ul ul ul ul { background: rgb(5,70,150);z-index: 9; }
div#menus ul ul ul ul { background: rgb(5,81,173); z-index: 9;}

/* lava lamp */
div#menus li.back {
    background: url(images/lava.png) no-repeat right -44px !important;
    background-image: url(images/lava.gif);
    width: 13px;
    height: 44px;
    z-index: 8;
    position: absolute;
    margin: -1px 0 0 -5px;
}
div#menus li.back .left {
    background: url(images/lava.png) no-repeat top left !important;
    background-image: url(images/lava.gif);
    height: 44px;
    margin-right: 8px;
}