Driver 's door key lock problem

[singring]

on my 1995 318i, I can only turn the driver's door key lock clock-wise, so the doors will lock fine. However, I cannot turn the driver's door key lock counter clock-wise, to unlock the doors. The key will only go as far as the "vertical" position. Luckily, the passenger door lock works fine, and I can enter the car, and unlock the driver's door from inside. I don't want to come to the situation where I cannot unlock the door at all, so I will drive my car, but I won't lock it.
Is this a case of replacing the lock cylinder? If so, can the cylinder be keyed to my existing key?

thanks

 

[grc]

do you have an extra key? have you tried it in the door? my lighted key was acting up like you describe but getting it "just right" would let it turn. i used my extra key today and i didn't notice any problem, could be the key is worn.