Why does my car stutter when idling?

What is your question?

When I come to a halt at a red light my car stutters. If I don't keep the RPM's at 1000 the car will stall. I've replaced spark plugs and wires, but the problem has yet to disappear. Any ideas to what may be causing this problem? Also would anyone know where I could get cheap parts like bumpers, fenders etc?