whinning noise

I have a 2001 Grand Prix GT with the 3800 engine (no supercharger) with 65,900 miles. I just purchased it about 6 weeks ago. It has a whinning noise at about 1500 rpm that gets louder with more acceleration,(doesnt matter if car is moving or not) sound like it is coming from the alternator. My belt had some cracking so I had it replaced. I had the alternator checked they said it wasnt charging enough so I had it replaced I also had the battery replaced it was the origanal factory battery. This didnt stop the noise, the repair shop found a leak in my power stering pump and I had it replaced. The noise is still there. The repair shop said the noise is coming from the power stering pump, he said some of the noise will go away after 500 miles but I may never get rid of the noise because the pump is placed so close to the fire wall on the 3800 motor. I can't imagine GM would have a car out there making this noise becasue of a design error?? Any help would be greatly appreciated.
Brad