remove the div, put this whole code inside the table.
i personally don't like the way your site is coded, as i can see its all divisions and ul's... for your site, especially yours, i would of set a table.
Your site does not have a billion columns or rows... its a really basic design, and i think you should stay basic.
CODE
<div id="header"></div> // to call your header, put some css to style it up a bit.
<table border="0" width="800">
<tr>
<td width="150" valign="top">
your navigation
</td>
<td width="500" valign="top">
your main text and content from word press
</td>
<td width="150" valign="top">
your advertisment
</td>
</tr>
</table>
<div id="footer"></div> // your footer plus some css to style it up a bit.
What you will than do is add your navigation code, which can really be made simple, couple css lines with mouseovers and bg colors... basic...
Add the codes of adverts at the place you want...
(really basic stuff) since you actually do not have images..