I want to buy some stuffs for making royal icing. what is the best place for it ?please can anyone help me.?

i live in montreal. and im new here.. im searching a store from where i can buy all the stuffs that i need to make a birthday cake...or many others.. so can any one help me out pleassse...such as.. confectioners sugar, meringue powder, light corn syrup etc.. pleassse need help badly...