.Herms.
Okay, I have a guess. I'm not completely sure on the reasoning, and I don't have my books with me to look it up, but I'll go on what I have for now.
The Grey Lady, aka Helena Ravenclaw, aka the ghost of Ravenclaw.
Reasoning
I once dwindle among the prestigious-she was the daughter of one of the original founders of Hogwarts
I am now what you’d call free-she's dead now, so she's free, but not in the obvious sense of the word
I’m the apple that fell far from the tree-here, i get less sure...i can't remember exactly why/how, but i think i recall that she disagreed in some way with her mother, and i know she took the tiara and ran off
Power and money I now lack-she's a ghost, also, she ran off from her mother
Three loves of mine have been attacked-again, not so sure...i feel like i remember something about this, but i'm not sure. I know the bloody baron killed himself after trying to bring her home, and he felt unrequited love for her