Finding metric screws or nuts is hard in Montreal.
Here is some adresses and links to help you out.
HARSUPCO 8330 bvd St Laurent (He has everything you need, you name it.) Update 31 mars 2021, now closed ! :(
COURS A BOIS VILLENEUVE 2 rue Bellechasse (They only carry starting M4)
http://www.ebay.ca/usr/northenmoi (He has everything you need! Ships from quebec, in 12/24h at your door. Shipping is cheap! (2-3$))