ORIGINAL: tIANci
I say get a new wing ... sorry but its much easier. If you saw the wing yes it comes apart but anyone thought of the solution for the spar? Don't tell me you want to use a router to remove the spar from the cavity?
A new wing is definitely the easiest way to go, and it may come to that if the halves do not separate easily.
The problem is that they want $80 for a new wing. I would just get the whole ARF for $115 and have some more spare parts.
I think you should be able to saw the halves apart, clean them up, and get the proper dihedral, even if you have to build some shims, as Hossfly suggests. I wouldn't worry so much about the looks of the joint, when you get 10 rubber bands on there, you can't see much of it anyway.