If your knees are up to it you could consider turning it into a single-speed. If not, or if your commute is too hilly, you could use an IGH... but that can get expensive really quickly, especially if you want new parts and/or someone else does the work. I bought my IGH bike because winter commuting is murder on my drivetrain and I don't want to replace/refurbish it every year. I am hoping for a relatively maintenance-free winter this season.