Logic pro 7 has a noise reduction plug-in, I have yet to use it so I can not say of its quality, but give it a try, might take out the hiss. About the sustain pedal... I don't think you can do much about it, the noise from the pedal is her playing style. The only way would be to rerecord the piano and tell her not to stomp down on the pedal.

For the sake of authenticity, I never gate or reduce the mechanical sounds of a grand pianoforte. For reduction of them, simply move your microphones about 3 feet from the case, pointing toward the reflector (Lid).

The pedal noise, the lyre and dampers in the action; all of that will be reduced significantly. I always use some form of rug under the instrument and a damp the microphone stand bases as well to reduce floor interaction (rugs under them help)

Think of it, do you want to capture the piano as the pianist hears it or how an audience hears it?

about the hiss, it's happening from either noise "occuring" in the room, or in the signal path between the mic and the soundcard. check every thing, (cables/connections/pre-amp/line out/etc...)you're only as strong as your weakest link. about the noise reducion plug-in,,,BE CAREFUL WITH THAT!!! i probably wouldn't use it because what happens is you create a faint "computor garble" sound in it's place that you won't always here right away,, but might hear it after it's bounced, burned, and in the cd player of the listener. i would use the multi-pressor plugin and use the expandsion features (but not too much!!!!) this plugin takes time to get good at setting,, but i can go further into detail if you'd like on approaching that hiss with the multipressor.