Hum... I would probably buy guns and lots of ammo, and study/ learn to shoot in the meantime.
Then I would go back to, I don't know, 1400 and teach the Incas about modern war technology.
I would like to know how Europe would react to that. Would they accept Incan Empire? Would there be wars? How would their cultures assimilate one another?
And as a bonus, we wouldn't have a genocide.