When you have Togekiss, use a heart scale to make it remember Aura Sphere. I would suggest replacing extrasensory with Psychic unless you haven't beaten the game yet (since Extrasensory is only better in that it has more PP, meaning less trips to the Pokemon Center.) If you need a Pokemon that knows Fly, teach Togekiss that. If not, teach it Air Slash (Heart Scale) or Aerial Ace depending on whether Attack or Sp. Attack is higher. Teach it Return (to take advantage of the high friendship that went into getting Togetic and STAB) or Extremespeed (also Heart Scale.) I wouldn't recommend this for serious battling, but Metrenome is a fun move to have. Flamethrower and Shadow Ball are some other viable moves.
My reccomendation: Aura Sphere, Return, Air Slash, Psychic (or Extrasensory.)