The obvious answer would be either your damage reduction or your damage output.
If you feel you can't take a few hits in act 3 and keep dying, buy more resists and armor and for sustain, get LOH or life steal.
If you don't kill things fast enough, upgrade your dps.
You can also use a formula to see how much damage you will total with new gear so you don't have to buy it to test it out. Whichever gear upgrades you the most dps for the least money is what you should buy.
Formula is roughly
1. 24.5% crit chance x 211% crit damage = (.245 x 2.11) +1 = 1.56169
2. 2057 DEX x .01 = 20.57 + 1 = 21.57
3. 1.88 atk speed
4. 385-909 dmg= average damage = (385+909)/2 = 647.
Finally multiply it all out = 647 x 1.88 x 21.57 x 1.56169 = 37,228 DPS
I am surprised that you can solo Act 3. What build do you run? I am also a monk with slightly higher stats. I have 40k unbuffed, 600 combined resists and still farm act 2.. maybe I just am not that good a player? hah.

Wrong thread? :)

I'd probably get an amulet, but because theyre camped so heavily I doubt I'd get anything good.

I think gloves are underrated. If you can get elite trifecta gloves, you will see a gigantic increase in your DPS. Trifecta amulets are also very strong. I don't know the benefits of that immortal king set, but as far as rares go, I think gloves/amulet are the way to go. Personally, I feel like most weapons/armor are overpriced and most people can get by fine on much cheaper gear. Trifecta rings also, I think the stat rolls are too low. But get the best possible AS/CC/CD gloves and amulet if you want raw power.

So far I've been rather conservative and purchased the following:



The rings are just an experiment as I still have the Legacy of Wicked Dreams set and I use them for farming.

Gratz Khan!