Health food store
I second the ordering in from Lowcarbgrocery, delivery is quick and they have so much stuff. I used to come into Edmonton for Sweet Tweet, but even with shipping it was better for us to order it online. They also have a frequent buyer program where you get money off your order if you get enough points.
Also, try sticking to real (natural) foods and avoid fake sweets, get your sweet tooth via fruit and even sugar free jello. You can find all the food you need in the produce, meat, and canned bean/lentil isles of any grocery store. I didn't eat fruit or any sweet for the first year and a half, frankly I wish I would have never reintroduced sweet back into my life. You also have to carefully watch out for sugar alcohols in fake sweets as well. I haven't gone to this specific store myself, but I would rather spend my cash on proteins. Good luck on your journey! It is very exciting.