Hey everyone, pretty new player here and I got some questions.

Yeah so I'm somewhat new to the game (I have like 35 hours on steam) and this is my Karak: http://i.imgur.com/7bKiyvL.png

My Problem is: I'm on Europa and my Karak is barely killing the enemies, and i'm not even starting on the Bursas'. Also I tried a T1Defense and I struggled really hard on the 10th wave. What do I have to do now? Potatoe? Equip other mods? Build a new Weapon?

I'm honestly out of ideas and would appreciate any advice. Thanks!