Yeah, sounds like you need to set up port forwarding. Since this is your business, and I'm guessing you might have a server or something with financial information, etc...I personally would manually set up port forwarding and NOT enable uPNP on the router. With uPNP enabled, your router settings are easily changed by your computer...which is fine if your computer is secure. However, should you ever get a virus, that virus could change your router settings...potentially giving hackers much easier access to your network. Setting up the port forwarding manually is not difficult...but it is tedious. It can be frustrating if you don't carefully follow the directions and get the appropriate information input in the right spots in the router settings. But worth it to keep your router more secure.
