Can't center my header

[katie hunter]

Hey,

I am trying to center my header but it just doesn't work, i tried playing around and still didn't get how to center it.

or trying to use a bigger banner , width wise

I can't even use a bigger banner =/ current default width 516, if i use a banner around 700 width, it doesn't show it all, it only show it until the 516 width, i tried to edit the header code from 516 to 700 and the banner was even more messed up.

Header code

<!-- logo -->
<a name="top"></a>
<center>
<table border="0" width="100%" cellpadding="0" cellspacing="0" align="center" background="$stylevar[imgdir_misc]/header_bg.jpg">
<tr>
<td valign="top" width="296"><img src="$stylevar[imgdir_misc]/header_left.jpg" width="516" border="0"></a></td>
<td align="right" valign="bottom"><img src="$stylevar[imgdir_misc]/header_right.jpg" alt="" /></td>
</tr>
</table>
</center>

<!-- /logo -->

<!-- content table -->
$spacer_open

$_phpinclude_output