Q: all the bolts are rusted on the header, and i do not know what could happen if any of them were to break!
A: Exhaust manifold bolts are famous for getting very rusted. If one of them breaks off, it can be a real pain getting it out. Unless you are a good mechanic, I wouldn't recommend you try removing them. Take the car to a repair shop and let them deal with it. You will need a drill and bit and an easy out to remove the bolt, if it comes out. They sometimes require being drilled out completely and the hole re-threaded.