Just add these codes to top of your postbit_legacy template.
Advertisement will show above the last post.
PHP Code:
<!-- Advertisement post code-->
<if condition="$post['islastshown']">
$spacer_open
<div style="padding:0px 0px $stylevar[cellpadding]px 0px">
<table class="tborder" cellpadding="$stylevar[cellpadding]" cellspacing="0" border="0" width="100%" align="center">
<tr>
<td class="thead" style="font-weight:normal" align="right">
<a href="" target="_blank"><strong>Special Link 1</strong></a> |
<a href="" target="_blank"><strong>Special Link 2</strong></a> |
<a href="" target="_blank"><strong>Special Link 3</strong></a> |
<a href="" target="_blank"><strong>Special Link 4</strong></a>
</td>
</tr>
<tr valign="top">
<td class="alt1">
<!-- message -->
<div align="center">
<!-- Advertisement Code Goes Here-->
</div>
<!-- / message -->
</td>
</tr>
</table>
</div>
$spacer_close
</if>