Tank bomb - need help/suggestions

Hi there
Right now I have a lvl 61 tank templar
this is my spec so far http://www.pathofexile.com/passive-skill-tree/AAAAAgUABAcFWwx9EH8ZhRoyGmwdFB8CJIskqiftKMUpTzEBNYA2xTbpOtg8BT0PPV9DY0SrRtdMNU3YT31RYFJTWPVdxmBtZp5wfXFNdhF8u31Tfq9-4oBWgpuFxYi6i4yMdo-ml5Waz52Ana6dxJ_fpwiplbcxuJPE9saezLfVddgk3QXd896w4XPjauOC5CLmfOcL7DjtIPLO877z3frS

Game play: 1. Curse group
2. run into group,
3. Taunt
4. Molten Shield probably explode
5. Shock nova

Auras: Tempest shield, Clarity and Dicipline/Purity

Stats: 49% block chance with tempest shield
82% to all elemental resistance with purity:
850hp
1100es

Molten Shield: 1760 dps
Shock Nova: 741.4 dps

My problem is I dont feel I can do enough damage or however tank probably.
I have no trouble, killing a group of normals mobs, but when champions or bosses enter the fight I kinda have to relate to kiting which is boring and slow.
Also when i am in parties I kinda feel im very useless, since everyone has big aoe, where my dps kinda depends I tank, which can hurt a lot.

Fighting in act 3 atm.


Any suggestion for some gems, skills or other gameplay strategies?
Can it even pay off to depend on tanking rather than just blast the target with w/e you got?