Get in contact with the local sailing club or yacht club ..years ago a mate and ai took a 16ft skiff to Cairns on top of a Kombi van , we didnt have sails or a mast for it, but once we arrived in Cairns we went to the Yacht club and Yorks Knob sailing club and some one had an old set of sails and a an old mast...if I recall correctly we got them for next to nothing..
Sailers are a pretty helpful lot..another option is gumtree ..