POS addon to OpenCart

I have a simple project and I am building a web-store to add sales to my brick and mortar store. I sell electronic gadgets and parts for them. I am using opencart for the webstore and have a simple POS computer that I would like to use as a cash register in my store, I now have another location and need to use multiple users now, so would like this POS system to be web-hosted (for multiple users at multiple locations) for use with any touchscreen computer and a web connection with a usb receipt printer, however a locally run software that works in windows and connects to the opencart database is fine too. My needs for this project are simple. I need it to print a receipt of the sale to USB POS printer (58mm); I would like it to "print" the TOTAL and CHANGE to a 2 line POS VFD Pole Display; (works like a printer) I need it to connect to the same database as opencart, so that when I sell a product in the store, it is taken from inventory and the website cannot sell it. (and vice versa);Other items like price, specials, description and other product related fields should be synced as well. I need it to be able to associate the sales with specific salespeople (so I can calculate their commissions at end of day) I need it to be able to search products via UPC code from bar code reader, I would like to print barcodes on the receipts to search out the sales as well by scanning barcode on return receipts. it needs to be secure and only accessible via the admin dashboard of opencart it Should use VQMod whenever required so as to not over-write any existing OpenCart files and the POS has touchscreen, so large easy to use buttons would be preferable. Only needs to handle cash and bank card sales. website receives all payments via e-transfer. I have the website up but not live, and am ready to hire someone get this working asap. If you can do this project well and quickly, I will have other projects as well that I would like to do using the same database and they can go to you as well. Serious bidders only. Copyright Transfer: You agree that all code created and copyright / ownership will be transferred to me in full at project completion. You also agree that you will not sell, share, rent, lend, display, give or use the code after ownership has been transferred.