I have a sign in button as shown below and when I try to click that the menu opens in which I am having an ASP.Net login control which is shown below my slider and not above it.So I would like to position it on top of my slider.And between my slider and sign in button I have menu bar.
So how do I do that?

I have followed this question on SO but did not succeed
This is my CSS:
#container {
    width:780px;
    margin:0 auto;
    position: relative;
}
#topnavsignin {
    padding:10px 0px 12px;
    font-size:11px;
    line-height:23px;
    text-align:right;
    margin-top:-60px;
    margin-left:120px;
}
#topnavsignin a.signin { 
    background:#88bbd4;
    padding:4px 6px 6px;
    text-decoration:none;
    font-weight:bold;
    color:#fff;
    -webkit-border-radius:4px;
    -moz-border-radius:4px;
    border-radius:4px;
    *background:transparent url('../images/signin-nav-bg-ie.png') no-repeat 0 0;
    *padding:4px 12px 6px;
    margin-left:420px;
 }
#signin_menu {
    -moz-border-radius-topleft:5px;
    -moz-border-radius-bottomleft:5px;
    -moz-border-radius-bottomright:5px;
    -webkit-border-top-left-radius:5px;
    -webkit-border-bottom-left-radius:5px;
    -webkit-border-bottom-right-radius:5px;
    display:none;
    background-color:#ddeef6;
    position:absolute;
    width:350px;
    z-index:100;
    border:1px transparent;
    text-align:left;
    top: 24.5px; 
    right: 171px; 
    margin-top:-55px;
    margin-right: 0px;
    *margin-right: -1px;
    color:#789;
    font-size:11px;
    padding: 5px;
}
This is how I'm showing it:
<div id="container">
   <fieldset id="signin_menu">
    //Asp.Net Login Control
    </fieldset>
</div>
//Here goes my Navigation menu
This is my slider part
<div id="slider_wrap">
            <div id="wowslider-container1">
            </div>
 </div>