Most models of cars can be re-keyed. You can order a complete set of locks from a motor parts store or a locksmith. Also, a locksmith can re-key your existing locks.
You should be able to find a shop manual at your local library with the right info...make copies as they are usually only in the REFERENCE section....good luck:)
What I would suggest is getting graphite oil.Put it on the key,then unlock and lock the doors.You can also use stuff like WD-40,Liquid Wrench,or Ballistol.(IMPROVE) Graphite can be EVIL for locks...
It is actually easier then u think its is basically just like your front door u have to by the new lock and install it on the car and then og buy a new key for it