Hmmm... not familiar with your area, but here are some flowers we can do here in pots for winter. I get few days below 30F or so here, and almost never have minimum temps below 20F.

Mums
Asters
Pansies
Violas
Flowering kale or cabbage
Dianthus
camelias
rosemary
Snapdragons [will take mild freezes only]

Part of it will have to do with where you set some of these plants. On the north side out in the wind wouldn't be advisable, for example.

In pots you just have to try Cyclamen and some of the autumn/winter-flowering Crocus.

Cyclamen produce either flowers or leaves, or both, during the winter. C. coum flowers throughout the winter, while C. hederifolium flowers in autumn and then produces attractive patterned leaves that last until it gets hot. Avoid the big flroists cyclamen that flood the shops about now, they are not frost-hardy.

There are lots of autumn Crocus flowering around October, but you can extend the season right through winter. C. niveus is a good one for flowering in November. Following that you can try C. laevigatus, where the most common forms flower in December and January, then you can pick forms that flower in very early spring if you want.

Local nurseries will have demonstration planters showing combinations of suitable plants, as they are always trying to get people to shop at other times besides spring. Southlands, I think it's called, near Marine Drive could be one of the more interesting places in town. (They have a web site). You might also be able to get some something you might like to try by visiting UBC Botanical Garden off Marine Drive or VanDusen Botanical Display Garden on Oak Street.