Yes.
You may want to try visiting Legends, Toy Wars, Toys on Fire.
I am not really familliar with the prices and selections at Toys on Fire but you can always call before going. Here's their contact info. These are stops for collectors so the prices are higher in most cases than what you find in Walmarts. I ommitted mentionning stores that carry a very small amount of Joes such as Capitain Québec, since I believe you might have limited time and distance to cover the map. Anyway, just google the addresses and you're on your way.
Legends Action Figures
7378, Rue Saint-Hubert,
Montreal, QC H2R 2N3
514-277-1867
Toy Wars
5535, boulevard Decarie,
Montreal, QC H3W 3C7
514-544-8969
Toys on Fire
1539, avenue Van Horne,
Outremont, QC H2V 1L4
514-948-2627
EDIT: Oh, and I hope you have a great time in Montreal! By the way, the stores I mentionned are on the Montreal Island, and you're going to be on Nun's Island which is going towards the South Shore. I think there is a big Toys R Us in Brossard, but I can't say more than that. That area is out my league. But we have a few Southerners on board who can give you a few directions to a store nearby that I'm sure.