Instead of buying the same bumper that was in your car before I'd go to
www.ddmtuning.com and purchase an M3 bumper instead, it's aftermarket but the build quality is really good, it will make your car look way better and plus you wouldn't have to pay close to 1000 dollars for a bumper from a BMW stealership, Their M3 bumpers for your car are around 360 bucks plus shipping from California ($125)
As for the other mechanical parts you can get them for a very good price at
www.autopartsway.ca (what's also great about this company is that they have a Canadian counterpart so you don't have to worry about customs brokerage fees and also, any orders above 75 dollars they ship it to your house for free)
There's also
www.bimmerspecialist.ca but I don't know if they have free shipping