consider using the path-arraykey in your module Result:
// some module code here
...
...
// Process template and set path data
$Result = array();
$Result['content'] = $tpl->fetch( 'design:foo/bar/blaa.tpl' );
$Result['path'] = array( array( 'url' => false,
'text' => 'YOUR NEW PAGE TITLE HERE' ) );
Or take a look in extension/ezfind/modules/ezfind/elevate.php . This is a nice example...