Need Marauder DPS tips

Hello,
I would like you guys give me a helping hand in increasing my damage. Ill link my gear and of course my passive skill tree. I'm using to be honest only 1 skill which is ground slam and kite a lot in maps, but I feel my damage is low while watching all the streams and reading chat with people spamming immense DPS.

Passive skill tree:

My Gear:


The reason I'm having blood magic as a gem for ground slam and not the passive skill are the auras. I'm using wrath and anger with blood magic/reduced mana and losing around 300 HP from that. I'm having around 5.1k hp (+300 reserved for wrath and anger) while mana is enough for 2 fast leap slams and haste+vitality+determination.
I took the 4 attack speed increase nods around center-ish of the passive skill tree because they boosted my DPS way more than any 12-8-8-8% phy. damage increase skill nods.
My DPS on ground slam is 2443, 2636 with Haste up and 3566 with Added Fire Damage and Haste.
Problem is I can't use that Added Fire Damage because I don't have enough mana left even if I would I could not spam Ground Slam so I replaced it with blood magic. Therefore in combat my DPS is 2636 unless I get a 6L chest where I could add the added fire damage...
Anyway the next 3 levels will be for a 8% Life nod in the north, 2% life leech and Elemental Adaptation.
So any suggestion on changing support gems? Or maybe a better way to spent my skill points?
Thanks in advance.

Use wurm's molt instead of switching out a gem for blood magic. Toss one of your % auras if you don't have enough reserves. You don't really need to go so far into the witch tree for those hp nodes. Switch them out for the damage bonuses near the beginning. Switch out your Astramentis and replace it with a carnage heart. Switch out your life leech and put in another damage gem. You could also upgrade your gems for quality ones too. Near the templar tree, you can switch out those 3 str nodes for elemental damage. It's not related to your dps, but try using enfeeble or enduring cry if this weakens your survivability too much.