The "good" news is that this puppy passes close to the earth multiple times ... close enough for us to reach it with current tech. If needed we should be able to get a nuke payload to it many years ahead of impact, with plenty of time to position the warheads and blow them at precise the right moment in order to adjust its orbit just enough to miss us. The object is not to try and destroy it ... but, rather, to change its orbit by a fraction of a percent. If done early enough, that should keep it from hitting us.
Anyone ever read Thunderstrike? Good SF book. In that book a huge comet which would have hit the Earth was slowed up by maneuvering smaller rocks (asteroids) into it's path with shaped atomic charges. The impact of these asteroids with the comet caused it to slow by several dozen minutes and, thus, it hit the moon instead of the earth.
This also means that its relative speed is not that great. This will limit the damage on impact as we use a series of large nukes to adjust its landing point to precisely...Mecca.