you can't bring live minnows into canada so you'll have to get them in ontario. i assume you're going thru sault ste marie - there's many bait store along the way but you'll have to call them to see if they carry these. check out: http://www.baitnet.com/
they list most all bait dealers in US and canada.
we found them at a bait store outside of sudbury one time and they made walleye fishing almost too easy. however they are rarely carried as i don't think they are raised commercially and must be trapped and sold - a no-no in the US.