Edit your header template, and right under the <body> tag, you could do something simple like this:
<!-- logo -->
<a name="top"></a>
<table border="0" width="100%" cellpadding="0" cellspacing="0" align="center">
<tr>
<td align="left" width="216"><a href="index.php"><img src="https://vborg.vbsupport.ru/images/misc/vbulletin3_logo_white.gif" border="0" alt="Powered By Vbulletin" /></a></td>
<td align="left">
<p align="center">
<img border="0" src="http://20dollarbanners.com/images/portfolio/0505/01_ipower_468x60.gif" width="468" height="60"></td>
</tr>
</table>
<!-- /logo -->
Just change https://vborg.vbsupport.ru/images/misc/vbulletin3_logo_white.gif to your website domain / directory, and then change http://20dollarbanners.com/images/portfolio/0505/01_ipower_468x60.gif to your banner location.
If this is for the site you listed above, then the code I displayed above would replace your code:
<div align="right"><iframe style="border:0;margin:0;padding:0;width:468px;height:60p x;overflow:hidden;" border="0" scrolling="no" frameborder="0" marginwidth="0" marginheight="0" vspace="0" hspace="0" src="http://www.freespacechat.com/banners/advertising/?b=A29DFA5C3FD307D79F8EBD15E52C16A2" width="468" height="60"></iframe></div><br>