Online is your friend!! I am part of the boring-size-boobs club at a big B/small C, but I have chesty friends and they recommend reddit’s /r/bigboobproblems – this forum won’t let me link it, I’m sorry, but it’s very easily google-able. Look at the sidebar on the right – there is a wiki for measuring yourself correctly, and lists of online and offline stores, including some in Canada! Good luck!
This advice would be probably useless but I’ll try anyway, I had big boobs (a month ago I had surgery to reduce them) and the only way for me to find a bra was going to Brasil (I am quite far away but I travel often) and no only to buy sports bra, they even have sexy bras over there. But I think you can also buy them online. In case you travel, the town where I buy them is called Ilhota
I’m a 34i (small back, stupidly big boobs) and have had the most luck finding bras at Dillards (dillards.com). 1st & Curve is probably the best brand I’ve found for fit, comfort, and quality, at a reasonable price. They go up to an L or M cup, even in a band size as small as a 34. I discovered them while living in Vegas.
Hope that helps!