Double boiler pot
I'm going with the assumption that you're looking for a double boiler insert... If you're set on the west end, Golda's Kitchen has a retail location in Mississauga. Their web store lists a couple of high-quality double boiler inserts (and of course they'd be happy to sell you a matching pot if you like) - if either of them look interesting to you, you can click on their 'contact us' link to see if they have them instock (they have a toll free number you can call, or email if you prefer).
Having said that - if you are looking for a quick and inexpensive solution, it looks like Cayne's has a Nordicware universal one which fits over a 1 to 4 quart pan - it has a 5-year warranty and would be under $25 even after shipping and tax - so you wouldn't have to make a trek if you didn't want to. Depending on how often you expect to be using a double boiler, it may not make sense to overspend...
2885 Argentia Rd, Mississauga, ON L5N, CA