Well they should get to it pretty quick, a gas leak is pretty serious business and the utility companies treat it as such. When I had one that developed in mid winter at the street connection to my house, I could smell gas coming from a pile of snow at the end of my driveway. Within 40min of the call, they had a tech there, and once he confirmed it they had a full crew there 20 minutes later with a backhoe digging up the lines. I probably got lucky and caught them not busy, but still.
Anyway, good luck with everything.