Forget the Kung Fu if you've got Karate behind your belt. Drop the Taekwondo. Take up BJJ or MMA, or if it's in your area I'd strongly suggest Judo, either Kodokan or Kosen preferrably. You'll get an idea of what you'd learn in BJJ, but you'll learn a greater variety of takedowns and throws from Judo. Then, with a BB in Judo, cross train in some BJJ or SAMBO and you'll really have yourself a grappling game.