I just used Canyon Plumbing to add new gas lines for my stove and bbq. They charge $96 for the first hour, and then $24 every 15mins after, plus cost of parts. The guy who did my house did an excellent job.
I had a similar problem with mine fotze. I used Ace plumbing and they were in and out quickly. I don't remember what it cost me but how can you put a price on cheeseburgers.