I think Marc might be right, black palm is the usual choice for bow wood among aborigine people in tropical areas. I would definitely leave the arrows as is and consider the whole thing as a display. Whether or not its worth a lot of money, I have no idea. You might write a letter to the editor of PA magazine asking if anyone can identify this kind of bow. They would likely be able to have Dr. Charles Grayson take a look and tell more about your treasure. I'd also see what your friend knows about it, where he picked it up and such. Might get clues on how old it is at least. It sort of looks better than something made simply for a tourist, but tough to tell. You might look on ebay and see what is for sale there. If you don't want to display it or store it, you might put it for sale there and be sure to alert us all.
In any case, thanks for some interesting photos and congrats on your acquisition.