copy licence software to do stock updating

I have an old program that isn't available any more, I use its catalogue index to search inventory, and mostly to check stock and do invoices. My work is getting busier so I need it on more than one computer screen for other employees to access at the same time, so we need to put this on some kind of server and we can all access the program at the same time. So to clarify, we want to do live of stock between computer screens, if possible it would be great we can remote sign into this software, if not we can download it to each computer and the stock feed and catalogue updates can derive via the server. The Project budget is $200. This job can be done as it was attempted by a guy on freelancer, but he was a bit clueless on how to do a live stock feed, and his english was weak to get the message across to understand.