I would search craigslist and kijiji (Kijiji is totally dead out here but that must just be Vancouver!). On both you can also put up 'looking for' ads if you don't find what you want, and people can respond to those.
Alternatively, local forms also have classifieds with AWESOME deals and really good equipment. Additionally you can get cheap or free plants and fish that surpass the qualty of those in pet stores by light years. There exists an aquarium forum called GTA Aquaria... I suggest you google and sign up... I don't know what I'd do if I hadn't found BC Aquaria!
It may take you about 1-3 weeks of classified prowling to get an idea of what you want and then wait for one to come up. Just as a pointer you should be able to get a decent 5g for anywhere between $20-30 CND.