Tips to PUG Helena as an lv41 warrior (?)

[Milan Lame Man]

Ok I suck at any class, warrior in particular, so can anyone offer tips on fighting Helena with a lv41 warrior?
Problems:
1. I don't get aggro with windmill, she kills others first, then me.
2. I cannot cast Horn fast enough, always 0.1s late

So my current strategy is just pot with Horn charged and wait for the "arrow shaped tell", then release. I can end out a few hits and then charge horn ASAP.
It feels stupid but kinda works.
Any better strategy? I will use CS instead of WM next time but I doubt it will help. Also I am not sure why I don't get the aggro from her, I am always so close I feel her breath, and using windmill during the targeting of roots.