Unless someone has an extra set that they want to part with (which I think would be doubtful), I believe you have 3 options other than your posting here on CP.
1. Search for them on EBay, even though I'd think that option would be a long shot.
2. Have a local canvas shop make you a set, though they might end up costing more than option #3.
3. Order a set through your local dealer.