1998 Pontiac Grand Prix a grinding noise when I turn the wh

I hear and feel a grinding noise when I turn the wheel. I added power steering fluid the resivour because it was low and it was making a loud winding noise when i'd turn the wheel. The winding noise is a little more quiet now but now im feeling the grinding in the wheel expecially when I park the car. I dont feel it when im driving normally like around town, just at slow speeds. I dont know if its the power steering pump or the rack n pinion, im clueless. It also looks like my rack n pinion has a slow leak in it. But if you could please help me out, I would appreciate it.