I sounds like you just want to change the number of columns in the table. This would be the basic structure. You may have to play with the width and such.
Code:
<!-- breadcrumb, login, pm info -->
<table class="tborder" cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="100%" align="center">
<tr>
<td class="alt1" width="100%">
navbits stuff
</td>
<td class="alt1">
your stuff
</td>
<if condition="$show['member']">
<td class="alt2" nowrap="nowrap">
userinfo stuff
</td>
</if>
</tr>
</table>
<!-- / breadcrumb, login, pm info -->