I have the same engine in my wife's 2005 Highlander. You could use 10w30 Pennzoil Platinum (PP) and be okay for 7,500 miles. Pennzoil Platinum 5w30 would be okay, too, as would Schaeffer's newer 5w30 Full Synthetic (I'm running it in the Toyo right now) or the Amsoil 5w30 that Pablo has recommended.
If it's out of warranty (4/60k?), you could try Mobil 1 0w20 or Amsoil's 0w20, but you're better off sticking with the 5w or 10w30 oils.