TORSO

dot_clear.gif (42 bytes)The object of good body covering is to block the breeze while allowing ventilation and keeping in just enough body heat. Working at varying effort levels sooner or later makes lots of sweat. Enough of that and much of your insulation is gone.
Layers are the answer. You should start out barely warm, remove a layer or two after a few miles if you warm up, and have a dry layer to add later if the chill attacks.
Overdressing will cause you grief as you soon swim in sweat. Many thin layers will allow adjustment as needed. Think about having at least a dry undershirt to put on if you should stop for any length of time. That can prevent chilling while you sit, as well as nasty cold when your wet bod is again exposed to the cold wind.
Where to buy clothing.

Layer one is critical: have a wicking material like CoolMax next to your skin to keep moisture moving outward. Never a cotton t-shirt!. The bottom half can be layered also. Just remember that the outer skin of your tights needs to be wind resistant but still allow ventilation. And don't forget that your crotch requires a serious wind block.
When cold weather approaches, try keeping a log for every successive colder ride. What about the temperature, precipitation, pace; what clothes did you wear and how did they work? Invaluable this season and next, as you try to decide what to put on today.
Do check out Ice Bike, the best Winter cycling source on the web, for much more information.
Your LBS has clothing, but usually a small selection. Online, see Performance, or - best -Col D'Lizard. Kathy at Col D'Lizard sets the standard for real customer care.