From what I hear, Fruityloops is totally incapable of composing rich orchestral melodies. The only chance you have of doing so is to get a version of FruityLoops that has the piano-roll, and if you want to use a keyboard do two other things:
1. Buy an extremely expensive professional audio card that can handle the input from a MIDI keyboard/device.
2. Acquire the actual MIDI device.
Instead of going through those two steps you could simply mouse around with the virtual piano-roll device for about two years until you piece together note-by-note the orchestral melodies and harmonies and then place them in the appropriate time tracks (another month or so).
Sorry to sound so pessimist, I've got a very similar problem to yours, except that I haven't actually got the Fruityloops Producer in the mail yet (I already ordered it).
"The keyboard is mightier than the sword."
...2D map editor with parallax layering in the works (60%completed)...