Renault Scenic Immo/key problem?

Hello to anyone who can help me. I'm have a problem with my 98' scenic, i changed the batteries in both of the keys, and now the keys will not work the immobiliser nor the c/locking. i have been searching around and have come to the conclusion that i am going to need the '4 digit' code to reprograme both keys. Is there anyone out there who can help me obtain this 4 digit code, dont really want to pay main dealer prices....

Regards: Rob