Blend cake mix and instant lemon filling together with mixer.Add fruit cocktail, coconut and oil, then beat eggs until foamy and add to cake mixture. Pour into 13 x 9 inch greased cake pan.Sprinkle 1/2 cup light brown sugar and 1/2 cup chopped walnuts over batter.Bake at 350 degrees for 45 minutes.
Mix oleo, granulated sugar and evaporated milk. Boil for 2 minutes. Stir in 1 1/2 cups coconut.Pour on top of cake (when cooled).