Replacing an above-stove fan?

I had a little accident on the stove involving a pan full of oil and some big flames. By the time I got the fire extinguisher out, the blades on the fan above the stove had completely melted. The motor still works, just the blades are gone. Do I need to replace the entire above-stove unit, or is it possible to just get a new fan? Any ballpark guesses on how much this would cost? Thanks!