You do have the latest patch. I don't think exploring outside the temple complex in act 3 first should effect the quests inside the temple. People have run into problems that way occasionally if they found a quest item before getting the relavent quest, where the NPC would not recognize that they had it, but dropping the item and picking it up again in that case should get it seen and accepted by the NPC.
For tough battles, keep a finger/hand on the spacebar, and pause frequently to direct attacks or use potions, etc. The DK patrols were originally intended to be much tougher, so you would be forced to sneak past them, as the DK's warning when you enter that area implies.
