I see you used my logo, but you wanted to make it so the "Join Today" part of the banner would send people to the register page when clicked. So here is the fix and two new images for you to use to do this (this will also align the right banner that says "Join Today" over to the right correctly to suit your forums width).
Upload these two images to your "Images/Misc" directory.
If your using vBulletin 3.6.4, just replace all the code in your "Header Template" with this code below.
Code:
<!-- logo -->
<a name="top"></a>
<table border="0" width="$stylevar[outertablewidth]" cellpadding="0" cellspacing="0" align="center">
<tr>
<td align="left"><a href="$vboptions[forumhome].php$session[sessionurl_q]"><img src="$stylevar[titleimage]" border="0" alt="$vboptions[bbtitle]" /></a></td><td align="right"><a href="register.php"><img src="images/misc/vbulletin3_logo_white_right.gif" border="0" alt="Join Today!" /></a></td>
</tr>
</table>
<!-- /logo -->
<!-- content table -->
$spacer_open
$_phpinclude_output
If won't matter now if you use a fixed template or not now using the banner and the new code in your header. The banner will stretch with the width of your forum to look right.