The comet has grown larger than Jupiter, and can now be seen with the naked eye in the constellation Perseus.It is said to be, like the shoemaker levy collision with Jupiter, a once in a lifetime event. I'don't know how far away it is, but I'll paste to a link in comments with more technical details, (and a better picture) in comments.

This website has some more details
http://cometography.com/pcomets/017p.html