To replace the lock you will need to locate the little tag that was with your keys when you bought your car as it has the number you will need to give to your car dealer to order a new lock. If you don't have the tag or key number you'll get what ever they pull out of the parts bin and the key will be different than what you have now (a real pain).
You'll need to get to the lock from the inside taking the panel off and any wiper motor or other latch hardware blocking access to it. Some cars are easy to get into some not.
Check with your insurance carrier before you start if you have coverage on getting it replaced (saving you cost & the pain).