We've been doing a number of winter cycling workshops and one of the points we have made is that you do not need cycling specific clothing for winter cycling...
They key to staying warm and not overheating (this is a bigger problem) is to wear a number of layers consisting of a breathable base layer, and insulating layer, and a windproof waterproof layer... if it gets diabolically cold then more insulation will be required.
Good gloves and boots are essential and again, that breathable base layer is crucial.
You will lose more heat from your head than anywhere else so protecting that is a must and being able to cover your face to prevent frostbite is another key.