renault key not working properly?

the petrol flap on my renault megane will not open. It appears to be locked and using the electronic key does not release the lock. We have fitted a new battery to the key but it still wont work. Also the key lights flick on when you press the key to open the doors but they don't unlock. I have to manually unlock the door with the key.

This is a despirate plea as I can't drive my car because I have no petrol in it and cant get into it to fill it up!!!!