[Digital Jedi]

That would be in your postbit_legacy template. Look for this block of code (NOTE: Might look a little different, since my vB4 is slightly older.)

			<vb:if condition="$show['reputation']">
				<span class="postbit_reputation" id="repdisplay_{vb:raw post.postid}_{vb:raw post.userid}">{vb:raw post.reputationdisplay}</span>
			</vb:if>
			<vb:if condition="$show['avatar']">
			<a class="postuseravatar" href="{vb:link member, {vb:raw post}}" title="{vb:rawphrase {vb:raw post['onlinestatusphrase']}, {vb:raw post.username}}">
				<img src="{vb:raw post.avatarurl}" alt="{vb:rawphrase xs_avatar, {vb:raw post.username}}" title="{vb:rawphrase xs_avatar, {vb:raw post.username}}" />
			</a>
			</vb:if>

The code in red is your rep code. The code in blue is your avatar code. Just switch places.

As far as aligning left goes, that should be it's alignment by default. But you might be using a skin that has different CSS. See if the original designer can clue you in to where he/she coded it to center.