I am looking for any program that I can create piano compositions just by plugging in the notes onto the staff, setting the tempo and what not. Basically like something similar to PowerTab, but for Piano.

Any suggestions?
That's a good choice, because you can then simply export the MIDI and apply it to a track in a sequencer with a decent piano plugin. I would take a look at Sibelius, which is really top notch for this sort of thing.

Doesn't come cheap though.
There is poetry in despair.