If the "attacker" is successful at winning the majority hashrate to defeat the fork, I expect a dump down quickly to $7 out of the corner of currently closing wedge.

Might get a bounce from there as many might perceive this as a victory for a decentralized Ethereum, although then potentially start the lawsuits from all the DAO losers. So a bounce could later be followed with a series of declines, eventually taking it down < $1. But as you say, this might take a while.

There are other scenarios though.