It's already in the footer template, so you can just edit the footer template and move the code for that ad. It looks like this:
Code:
<vb:if condition="!empty($ad_location['ad_footer_start']) or !empty($ad_location['global_above_footer'])">
<div style="clear: {vb:stylevar left}">
{vb:raw ad_location.ad_footer_start}
{vb:raw ad_location.global_above_footer}
</div>
</vb:if>
and is at the very top of the template.