Jumpr,
Congrats on taking the plunge into commuting the full trip. Like everybody else has pointed out you don't really need all the expensive gear for a 25 min. ride. Try a couple of light layers under a windbreaker, some regular winter gloves and a regular hat under your helmet and you're probably set for most days. You might want to skip riding on really rainy days, since that can be miserable without good rain gear.
Definitely get some lights -- even cheapies from an X-mart will help you be seen by cars and avoid accidents. Meanwhile enjoy the ride and don't worry too much about the gear. Most things can be made to work out fine.