Hiya, first of all, just so you know I think it's spelled "tourtière" (this will help for searches)
I'd suggest trying:
Ma'am Bolduc - funky, cozy decor, friendly service, amazing sugar pie (tarte au sucre)
4351, avenue de Lorimier 514-527-3884
La Binerie Mont-Royal - lunch-counter type place, many other traditional hearty Québécois dishes like fèves au lard (baked beans with pork fat) and cretons
367 av. Mont-Royal Est 514-285-9078
Both are inexpensive.
Neither is in the heart of downtown, but definitely worth the trip if you're from out of town!