I would recommend it, at least 1 point, why not? Plus defense never hurt anyone.
I would also add that a merc is a must, since you dont have max block, he will become your tank. Get an Act 2 defiance aura merc and equip him with a doom for holy freeze (or insight if you dont have the funds), shaftstop or fort, andy's helm or gaze. Makes life soooo much easier, especially vs Andy, since she will be standing still fighting ur merc and only attacking him, with his DR and psn res from andy's helm he should live to see another day, as long as you kill her quick with ur blizzz.