Banner ad in the header area

I’ve been trying to put a banner ad in to the header are and it shows up… but i can’t get it positioned where i want it. I don’t think the div i made for the ad is responding to the style sheet entry.

here’s the header stuff:
<div class=”Header”>
<div class=”Header-jpeg”></div>
<div class=”logo”>
<h1 id=”name-text” class=”logo-name”>
/”><?php bloginfo(‘name’); ?></h1>
<div id=”slogan-text” class=”logo-text”>
<?php bloginfo(‘description’); ?></div>
<div id=”banner_ad”><script type=”text/javascript”><!–
google_ad_client = “pub-5047356984378907”;
/* 468×60, created 4/20/09 */
google_ad_slot = “8203459468”;
google_ad_width = 468;
google_ad_height = 60;
//–>
</script>
<script type=”text/javascript”
src=”https://pagead2.googlesyndication.com/pagead/show_ads.js”&gt;
</script></div>
</div>

And here:s the style sheets part with the banner info :
/* begin Header */
div.Header
{
margin: 0 auto;
position: relative;
z-index:0;
width: 896px;
height: 225px;
}

div.banner_ad
{
float: right;
position: absolute;
width: 468px;
height: 60px;
top: 15px;
left: 502px;
}

div.Header-jpeg
{
position: absolute;
z-index:-1;
top: 0;
left: 0;
width: 896px;
height: 225px;
background-image: url(‘images/Header.jpg’);
background-repeat: no-repeat;
background-position: center center;
}
/* end Header */

What am i missing? Any help is greatly appreciated!!
Again… The ad shows up.. I can see a functioning ad.. i just can’t position it where i want.