Once your navigation menu is built you can amend the links a lot quicker and easier by simply editing the HTML code in the menu.php file located in CSSMenuWriter > cssmw.
If you open that page in Dreamweaver you'll see your menu is just an unordered list so add the new page names and links into the list where you want them to be placed in the menu. Save the page and (assuming your menu was originally included in the template files) your navigation should be updated site-wide.
Hope this helps you.