Just move the rank code, which should be something like this:
HTML Code:
<vb:if condition="$post['rank']">
<span class="rank">{vb:raw post.rank}</span>
</vb:if>
to within the <div> under the avatar code, which should be something like this:
HTML Code:
<vb:if condition="$show['avatar']">
<a class="postuseravatarlink" href="{vb:link member, {vb:raw post}}" title="{vb:rawphrase {vb:raw post['onlinestatusphrase']}, {vb:raw post.username}}">
avatar stuff here.....
</a>
</vb:if>