Unfortunately a keycard for one megane cannot be reprogrammed to operate the locks on another one. Each card is ordered from France, specifically by chassis number of the car. I'm afraid you've wasted your money on a pointless card! That's why Renault dealers can charge so much for them, because it's difficult to find anywhere else that can get hold of them from somewhere other than Renault themselves. Sorry.
Thomas Backalone, April 2008