Your not going to run a business behind a carrier grade nat.. Get a new connection would be suggestion 1.
Suggestion 2, get a vps somewhere. Run a vpn connection to that, and tunnel down any traffic you need to tunnel down into your actual location. But better yet would be to put the services the public needs to get to there in the first place.
Your not going to find a "vpn" service to do what you can do way cheaper and easier with a simple vps or multiple vps all over the globe, etc.