A store carrying GW (Games Workshop) paints should have Badab Black readily available ... even in Canada ;) You are talking about a store having Warhammer material, so I assume they carry GW paints too.
As for brand I would recommend GW in general. But honestly, ask ten people here and you will get ten different answers. If you can get any of the (acrylic paint) lines made for miniature painting you can't go wrong (for starters ... ;)): GW, Valejo, P3, Reaper, Coat d'Arms, ...