If "power steering pump pullley is wobbling", do I need to replacement it immediately?

It depends,if the pulley is bent, it could throw the belt which could cause other problems, broken fan ETC. But you will loose your power steering, which if you are in or going into a turn may cause you to lose control and hit someone(car or pedestrian). If the shaft on the pump is bent same thing can happen. If it is just the pulley that is bent, then depending on the model you may be able to just replace the pulley, but if it is the shaft then the pump will need to be replaced. If you ignore it the problem will not go away by itself. Pay a little now, or a lot later(cost of a life, yours or someone else can't really have too high a price not to fix the problem)