By FR i would assume OFR? E-bay if not, you could buy the Gotoh or Schaller FR's. I think Gotoh's can be bought at Davis for about 80?
Installing a FR onto a fixed bridge guitar IS possible... just needs alot of wood routing for the cavity at the back so its not really reccomended though + The labour to route the back of the guitar and all + an OFR would probably cost more than a new guitar with an existing FR