If you edit your template's index.php file and at line 229 you will find:
<?php $today = date("l, F j, Y"); PRINT "$today";?>
Change that to:
<?php
date_default_timezone_set('Australia/Sydney');
$today = date("D M j G:i:s T Y");
PRINT "$today";
?>
You'll see I set the time zone to Australia/Sydney, if that needs changed here is a list of available php time zone variables for Australia:
http://us3.php.net/manual/en/timezones.australia.php