1. Mud Boots
In the fall it starts to rain and in the spring it starts to mud. Boots like these from LL. Bean are handy.
2. Winter Boots
If you don't get mud boots, then definitely consider getting a pair of winter boots. It is a long walk up the hill in the winter, and you won't regret an investment in keeping your feet warm. Personally I have sort of a hybrid mudboot/winterboot that I wear winter-spring. The mudboots might be good enough themselves.
3. A Thermos
A thermos is a great thing to keep you warm through the colder months. And there are apparently multiple benefits to drinking hot water.
4. A Raincoat/Umbrella
Lots of rain in fall and spring. And even this summer, actually.
5. Long underwear
Wearing long underwear under your pants in the winter months makes such a big difference, but a lot of people from warmer climates never learn this secret. The sooner you get savvy the better!
6. A Warm Winter Jacket
Lots of people have these hip and expensive Canadian jackets. Really any type of warm jacket will do, and if you can, treat yourself and go for the 3/4th length!
7. Wool Socks
You'll probably need a few pair that you can wear every day throughout the winter.
Some places where you can order this stuff: Campmor, Back Country, MooseJaw, Overstock, or places like REI, EMS, or Amazon. Goodwill has some stuff up here but it is often a crapshoot and the good stuff goes fast.