You could check a craft store to see if they have a molding kit for molding plastic. User your too-curved ones as a reference to make a mold, and make a new set in plastic (plast-aid or something similar). Even with the curve in the mold the plastic parts should have enough flex in them to allow use.
I'm certain you'd have to hand-work the back side of the plastic copies to fit; I don't know if the craft-type kits can do both sides, but if you search you might find something that can for not too much money.