Smooth sound, I like the arrangement and the choice of instruments.
I don't know if an instrumental piece can convey the message of a "love song" well, vocals would certainly help here.

To answer your question (which I also had a few moons ago), no, you can't go up an octave. When I need to, I either import the Paino's MIDI data into my DAW and transpose there, or I play it there all by itself.

Edit: I'm talking about RealTracks. MIDI-tracks can of course be transposed inside BIAB.