I would suggest that you drain the whole system including pump, pipes and injectors. Then replace a small amount of diesel in the car with a little injector cleaner.
You can put diesel in a petrol car, but not the other way round and (as has been said) diesel is also a lubricant and putting petrol in your diesel engine will have also removed any lubricating qualities that were in the fuel system meaning it will be under extra wear until lubrication starts up again.
It sounds like you didn't drive it far so it may be OK.