You don't necessarily need Dreamweaver, but you can open up the pages in Dreamweaver and edit the title there. You would just find the title tags and edit what is in between them to be the title you want. For example on the thankyou.php page, you would find this line of code:
<title>Thank You - <?php echo($WAGLOBAL_Site_Name); ?></title>
and change:
Thank You - <?php echo($WAGLOBAL_Site_Name); ?>
to display what you want. This part of the text displays the site name that you specified in the admin section:
<?php echo($WAGLOBAL_Site_Name); ?>