Spike, you can replace the power lock unit and all the related stuff. Get a manual for you car that cover the year you own. Just becareful taking things apart. If you have a digita camer take pictures of everything together in it's place inside the doors before you start. That will help you putting it all back together.
It'll be cheaper doing it your self than having a repair shop or dealer do it. Check your junkyards for what you need but make sure the power lock unit works. They can do that.
I've got the same issues with my 2000 Jeep GC. I've just been too lazy to fix it all. LOL