distributor rotor help

Im doing a little tinkering on my honda just to make sure things are in order. I figured i would take of the dist. cap and take a look. THe cap looks good. The rotor is what im worried about. It looks like the tip of the rotor has some corrosion. I would like to replace it but i cant get it off for the life of me. My manual says to losen the retaining screw and pry off with a screwdriver, along with a real bad pic. Any help would be much appreciated.

im retarded and i got the screw and rotor off. Now how much would it be to replace, as it looks a little corroded.