Two ways you could try:
1. Add a cell before the menu cell to force it to the right (you would need to remove the width or adjust the width of the cell containing the menu). Change lines 44 and 45 of your code to read:
<tr align="center"><td width="105"></td>
<td align="center">
OR
2. Centre the menu in a new div. Add div tags before and after your 'include (require_once):
<div id="menu">
<?php require_once("CSSMenuWriter/cssmw12/menu.php"); ?>
</div>
then add the following css style to the head of your document (in code view), say after line 12:
<style type="text/css" media="all">
#menu {
width: 825px;
margin:auto;
}
</style>