The Boss quest - How to take out Nelson

OK Any tips on taking out Nelson? I have the bank package and can carry 10 potions. I am a level 40 wiz. I have the gem purchase item that gives a + 20% block, I have the gem purchase item that gives +3 con, I am wearing unknown gods armor of life +3 (68 prot and +4con), and am wielding enchanted star staff (583 dam and +20% spell damage), my buffed con is 110, my str is 32, my int is 40, dex 32, quickness 32, and I have 145 learning points saved that I can apply to whatever will work. I am not close to being a dual class (level 20 fighter and level 23 gun guy), and Nelson has 42k+ HP and I do (with my ally hitting) about 200 point a pop using my best spell (maelstrom). I go thru all 10 dusts and am not even close to taking her out. Any suggestions?