Do not continue to drive it!
How much diesel was in the tank before the gas was added?
Did the battery die from you trying to start it again and again?
The dead battery may have saved your engine!
Tow it to a proper diesel mechanic and have the whole fuel system drained, cleaned and replace all filters. Depending on how much damage was done you may be looking at a new injector pump, injectors, all your emission control components. If it suffered detonation you could need a whole new engine!
I would be talking to the filling station owner about the cost of their mistake, but I would take it for repair somewhere else.
Forged, Stroked, Blown, Bottle Fed & More