"and the second question is how do you beat starkiller? i cant kill him! does anyone have a good strategy on how to rip him up?"
What I did was initially move out of the way from his first grenade toss and immediately throw a concussion grenade at him. This will stun him for 9 sec, should be enough time for you to tear him a new one.
Also, a little trick is before agreeing to the duel, use a power shield (?) to deflect his incoming blaster attacks. This way you dont waste time in the duel activating it.