If an Eros-sized asteroid hits Earth there will be no human race to tax for damage repair. It would be pretty much a game-ender. Nearly all life on the planet would be annihilated. The Chicxulub asteroid thought to have killed off the dinosaurs was only about 8 miles in diameter. Eros is much bigger. It's only a matter of time and celestial mechanics until such an disaster occurs, and I agree preparations are needed.
Technically its easy to prevent an asteroid impact. Its the money that gets us at this point. Given enough lead time, turning it a fraction of a degree or slowing it a by a few inches per hour is all it takes.
I personally think a gravitational tractor is the way to go.