help

please can any one help me i have a Nissan largo (sorry not a elgrand) but i think they are similar?? any way its 1997 20ltd sxg.wheni bought it i only got one key but then i spotted what looks like a sensor on the dash near the windscreen which i was told its a infer-red sensor for remote central locking ??
can i buy a remote fob so i can work the central locking, my wife is disabled so having the rcl would be a great help to me,
many thanks
maurice
sorry ive put this in the wrong post sorry?????