There is a 12V power outlet on the passenger side of the vehicle next to the center stack. It has a flip down cover over it. You should be able to use that for powering your Garmin C330. As for How long it takes to charge, I don't own one so I cannot help you with that.
I have a C320.... battery last longer than the C330... but I have been getting about 7-8 hours before I need to charge it again. Just plug it in when you get home... the screen will display a completed charging when its done.