What paypal system are you using ? Paypal Standard or Paypal Direct payment.
The easiest what to accomplish this and make sure paypal displays it is to conctinate the new column to the vartiable that passes the name to paypal.
if using paypal standard, there will be a hidden element on the confirm page similar to:
<input type="hidden" name="item_name_<?php echo $mdfCart_Index+1; ?>" id="item_name_<?php echo $mdfCart_Index+1; ?>" value="<?php echo $mdfCart->DisplayInfo("Name") ?>" />
you can add the student to the name using this code
<input type="hidden" name="item_name_<?php echo $mdfCart_Index+1; ?>" id="item_name_<?php echo $mdfCart_Index+1; ?>" value="<?php echo $mdfCart->DisplayInfo("Name") ?> - <?php echo $mdfCart->DisplayInfo("Student") ?>" />