Driving (and diving) from Mackay to Brisbane?

I will be driving from Mackay to Brisbane, starting either Thursday night or Friday morning. I need to be in Brisbane by Saturday afternoon.

Naturally I would feel pretty silly being in the area without getting at least one dive in.

Considering my time constraints, any suggestions for maximizing my dive experience?

I'm thinking probably a boat from Mackay, Gladstone or Bundaburg would be the way to go, assuming there are some good sites not too far out.

Also, any recommendations for good shops/operators to call would be appreciated. Thanks!

I guess one option would be to drive to Airlie Beach and take a two-dive day trip from there, but that would add another four hours in the car.