Elemental Shaman should drop poison cleansing totem and nature totems to make this a trivial fight, with that you should not have much of an issue really if your pushing 1200 SP and the poison is your only issue then nature and poison totems will make this fight easier, I had the same issue once I got past the first boss, the second boss would destroy me even with my tank being 80. I looked around and found that if I wanted to beat it poison and nature resistance totems would have to go down and this negated much of the poison damage I took even with my team standing in a poison cloud. Have fun and try it out and see what you think, you did not list weather you dropped those 2 totems so not sure if this will help you out.