This is not a supported modification of Power Store, the page that stores the order information to the database is the webassist/plugins/shopping_cart/store_cart.php page
you would need to edit the store order summary behavior to store additional information to the ps4_orders table. and you would need to add a store order details behavior to store information to the ps4_registrants table.
this goes beyond what we can help you with in the forums, if you require assistance, please sign up for a premiere support appointment.