Adding Google Adsense to Individual Posts

Hi,
I’ve been trying to add Google add sense to individual posts but all I’ve manged to do is bugger up my site. Fortunately I keep back up copies of the code & was able to fix nearly all the site but I’m still left with 2 issues.

1, I’m still unable to add google adsense to the bottom of individual posts.
2, For some reason I now have Google Adsense at the bottom of my site & I’m unable to get rid of it.

Here’s the link to my site http://www.smokincharliebrown.com/scb/
&
Here’s the Google adsense code I would like to add to individual posts

<script type=”text/javascript”><!– google_ad_client = “pub-8058972336873313”; /* 728×15, created 6/11/10 */ google_ad_slot = “4870161011”; google_ad_width = 699; google_ad_height = 15; //–> </script> <script type=”text/javascript” src=”http://pagead2.googlesyndication.com/pagead/show_ads.js”&gt; </script>

If some could please let me know how to add this code to individual posts on my site & how to remove the advert at the bottom of my site that would be very much appreciated.

Thanks,
John