Ad Banner

[stakmak]

Hello

I've been trying to figure out how to place an ad banner at the top of my page. I place my site in edit mode and I paste the following code in the area for the ad banner, yet nothing shows up. Here's the code I'm pasting:

<script type="text/javascript"><!--
google_ad_client = "ca-pub-2445026776981578";
/* specs generic ad 1 */
google_ad_slot = "7591236840";
google_ad_width = 728;
google_ad_height = 90;
//-->
</script>
<script type="text/javascript"
src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
</script>

I don't know anything about programming and I don't have the means to go to school for it or anything. I really just do what I can from internet searches. Do any of you see anything that I should fix in that code?