Those bikes are about $6 to 6,500 new. Currently, it's a 6 year old bike...so $3 to 3,500 would be the most it would be worth, IMO.
If you buy new plastic from a dealer, it will cost $4 to 500 at least...assuming there aren't any broken brackets, headlight assy, bent handlebars, or other such things.
You might be able to find plastic on eGouge, but it will be hard to find all matching colors.