Fingerless gloves are an option. And then there's this:

Cozy Mitts

I bought a pair for myself and another for a friend who has serious cold-hand problems, and we both love them! They have inserts that you heat up in the microwave (with lavender inside, so they warm your hands and provide a little aromatherapy all at once).

Or there's this, which appears to be an electric blanket for your hands.