BMW Car Key Question?! I Have a Couple?

My friend had this problem,she dropped her keys and somehow managed to break the key completely,i.e the plastic bit you hold came apart,while doing this she failed to notice that a little bit had fell out,all keys have this bit in and each key bit is for a certain car,if the key does not have this "bit" you wont be able to unlock automatically neither will you be able to turn your ignition on,she found the only way to get a new one that would work is to contact her local bmw dealership and ask them to make her a new one.This can be quite costly and you will need some details of the car.