Can someone help save my Blood Magic Tank build?

Started leveling my Marauder tank with a group of 3, and just went full tank to keep everyone alive. Been using Cleave, Molten Shell, and double Enduring Cry.

Now I'm almost 70, and I'm very very tanky. No real problems keeping everyone alive. I just don't have much damage or utility. My current build is:

http://www.pathofexile.com/passive-skill-tree/AAAAAgEABS0OPBLhFCAUcRkuGjgaVRznIPAkiyfVJ-0pLi3SNug6UjrYPQ89_ETnUEdQUFcNWGNfP2BLYSFko2oeajt07XrvfLh8u331hO-MBozPkFWRzp7Nnz6i6qSspzCnhKgYud3EFcRYxPbG2NIh2WHfv-w47w7yL_Pd9kg=

I still have a ton of potential passives, and I haven't spent any refund points. I'm still planning on staying with the group, I'd just like to do more than Tank and Taunt.

Does anyone have any ideas how to modify or extend this build to provide some kind of big damage boost, utility, or survivability, to the group?

Whats your dps on cleave and molten shell? Two handed or one handed? what auras you use? iron will linked to molten shell? its a great dps boost!

Very low. 300 and 800. Cleave I've got stun, life on hit, and life steal on, just to do something. But my group does pretty much all the damage. Thats why I'm trying to help in some other way besides standing there and taunting.

standard way to go is conduit if you take all end charges and one from oak its a great dmg reduction for your party!

I thought about that. I've been running 7 charges, maybe 8 if I use the unique ring I have... but then what is the range of conduit? Just a screen's worth? Also, if they have no Max Endurance Charges, they just get 3 charges, or 15% reduction, right? So it wouldnt matter what my max is.

yeah but it matters to you :) I made a little adjustment to your tree.
http://www.pathofexile.com/passive-skill-tree/AAAAAgEAAnEEswUtDH0OPA6tEH8S4RQgFE0UcRjbGS4aOB0UIWAn1SftKLUpLimlLdIyCTKJNuk6UjrYPfxAoEOcTdhQR1BQVElVxlYEVw1X4lhjWfNfP2BLYIhhIWFSZp5yqXTtdPF35XrvfLh82YTvhmCMdozPj0aQVZHOnrmezZ8-n8uiAKcIpzCnhKlorKq4k7ndu-3AGsRYxp7G2M9l0NDSIdSP2WHa3eNq51LsOO8O707yL_Pd9kj60g==
also Iron will on molten shell is a huge boost to dps. area of effect not so much, but a possible addition. I tried it, but liked increased duration much more!

also removed BM because its just not practical in end game imo. BM gem are much more of use for me! I have lvl 63 mara
http://www.pathofexile.com/passive-skill-tree/AAAAAgEAAdwB5wJxBLMFLQx9EH8S4RQgFE0ZLho4G_odFCXfJ9Un7SkuLdI26DrYPfxGaUd-TdhQR1BQVcZXDVhjWK9Z818_YEthIWVNZp5nm3TteA1673y4gW-E2YTvhymMdozPj0aQVZHOnjyezaIApBmnCKcwp4SrxayquJO53bvtvorAGsRYxp7G2M9l0NDSIdSP2WHi6uw47w7wH_Iv8932SPrS

almost the same :) use 7 end charges same as you, a lot more life regen ( now about 300 ps), FP for main dps and molten shell. Looking for another dps main source, bow or melee or EK, not sure yet. leveling all the gems at the moment to try out dps and usability.