Hi Maggie -- I moved to Calgary from Fort Collins, CO where I developed a love for Fat Tire and the beers of New Belgium Brewery. Sadly, their beer cannot be found in Alberta. At least not yet.
A great way to check is to use the Alberta Liquor Guide online search tool, which can be found here:
http://www.alberta-liquor-guide.com/LC/LCCONSUM.nsf/CatalogMain?OpenFrameset
Do you homebrew? I have a recipe that others swear is a dead ringer for the real Fat Tire (although I have yet to confirm this myself). Let me know if you want it.
Cheers!