You can also try brewtime
in Hamilton. They are up near the airport at
1638 Upper James St. just South of Rymal Rd.
or their branch location
38 Centennial Pkwy N.
across from East Gate Mall
I've bought some grains and hops from them before and they are trying to bring in more homebrew related stuff.
Nickelbrook is right on your way past Burlington though (right next to the Burlington Go Station), you can get pellet hops, grain, some standard yeasts. I've bought some pale LME there too, about $6 a litre.