Bon Jour Laureen:

You need to edit the file _class_itemlist.php, which is located in the b2evocore directory.

Look for the date_if_changed function. The parameters will be:
( $before='<h2>', $after='</h2>', $format=' ')

You need to change that to:
( $before='<h2 align="center">', $after='</h2>', $format='j F Y' )

This change also causes the date to align to the center of the box, instead of the left. Upload the file on to your web server and it should work.

Chris ;) / csadams.com