Barbarian lvl100 - what now? How do I get stronger?

So I got my Barbarian to 100. I see people at hell tides and such just ripping through enemies like a hot knife through butter but I don’t know how I get stronger now. I can manage the lvl100 six wave Infernal Hordes but I’m still pretty fragile overall.

What’s my best option to get some real significant gear improvements over my current iLevel925 legendaries. I’m doing a bleed build focusing on rupture. Everything that drops just seems to be a similar piece with very little improvement or worse over all. I can’t beat any of the tormented bosses, do I just need to grind Nightmare Dungeons, IH, and Pit runs and pray I get a super good drop that really cements a power increase?

Edited to add my current stats: Attack: 85,000 Armor: 9500 Health: 28,000

Thanks for any help!