Overwintering Herbs in Hanging Baskets

I am growing herbs in hanging baskets, around my vegetable garden. All the books I have tell me how to grow the herbs but, I don't know what to do with the herbs come winter. I am going to put them in my unheated work shop. Do I leave them? Do I cut them back? I live on Gabriola Island, a small island off Nanimo BC, Canada. I live in zone 8. The herbs I am growing are: Mint: Grapefruit, Pineapple, Chocolate; Rosemary, oregano, thyme, lemon balm, parsley, tarragon, sage, chives and basil. I understand that basil is an annual, any tricks to growing it, my plant did very poorly.

Leaving the baskets in your unheated garage would be fine just as long as you remember to water the plants enough so they don't get too dry. They must also not get too wet as this would make them rot or start into growth prematurely, and then get killed by a late frost.
Do not cut them back until spring – they will survive much better that way.
Your parsley should be overwintered in the house, because frost will make it bolt to bloom after which it dies. The blooming will eventually happen anyway, but avoiding frost delays it.
Basil likes lots of sun and heat -which may be hard to come by in coastal areas.