Weird power steering failure?

Hello,

Last week I was driving my 323i from 2000 with 104k miles when I noticed a lot of whining coming from the car. When I tried to park the steering was very heavy. I parked the car and checked the power steering fluids, there wasn't any ATF oil left.

Mind you guys, I've had weird acceleration problems the weeks before this. When changing to third gear and stepping on the gas; my RPM gauge got up to soon, and had too keep up with my speed gauge. I don't know if these 2 problems are related to each other? Anyway, when this weird revving happened I checked all the fluids, ATF oil was still in the car, altough not that much.

Back to the present time; I've followed some guides in order add ATF oil again. The first time I filled the car up with power steering oil, I steered completely to the left and the right as advised on some of the guides.
The steering remained heavy, the guides did told me to refill as needed because the steering system takes a lot of oil.

I checked the oil again, and it was completely empty. I filled the car up again. This time the steering got smooth for a little while.
After that the (loud) noise came back when steering, and got really heavy again.

I didn't had any more ATF oil so I stopped. Note that I did notice oil leaking beneath my car.

I'm really confused here, should I fill up again? Is the pump gone bad? Or is it simply leaking oil?

I've had my BMW for a full year now, this seems to be the first failure. Hopefully it isn't to bad

fix leak - probably a good time to flush and make sure no air in system
revs going up before speed means clutch is slipping