POS for Opecart with loyalty card reader - open to bidding

Looking for a POS ready made to modify for our businness. We already have some scripts done that you can see at : [login to view URL] we need to modify this existing script or make one from skratch . 1) handle tables in a restaurant 2) read the loyalty cards of the customers for the rewards all using our existing opencart . payment only at the end of the work , we found lot of problems and we lost lot of money already , from our feedeback you can see that we pay .