Hi JoAnn,
We're in a somewhat similar climate. My trees went through three nights of freezing temps a couple weeks ago, so I am waiting just a bit longer to determine what was killed from what seems to be hardening off. If it doesn't freeze, and if your tree doesn't appear to go dormant, then I would think January or February.
As for how much to prune? That's the neat thing about fig trees. There are so many ways you can do it. You can prune it to one inch above ground and it will come back as a healthy young tree and most likely produce main crop figs next year. You can prune it to a pleasing shape, or prune it way back like in the pics of commercial growers in Japan or South America that some have posted, or you can just top it, and/or thin it out a little...or you can just leave it alone.
In other words...you can't really mess it up. And if you aren't happy with how it turns out...you get a "do over" next year.