The next vague clue has been uploaded:
Aaaaand I'm confused. The piano in the photo hints towards Delta Goodrem moreso than anything else - since she plays it, and a lot of her songs feature heavy piano backings - or possibly Dami Im. On the other hand, though, [MENTION=4395]Schlagerman1[/MENTION]'s posted some pretty convincing evidence for Courtney Act... except for the fact that I can't find anything about Courtney playing the piano. A few brief Google searches mentioned nothing about her playing it, and the only photos I can find of her with a piano are ones where she's lying on top of one.
It might just be that Courtney can play the piano and I can't find any proof of it, but otherwise, we've got two pretty strong sets of hints that don't mesh together, and one's got to be a red herring.