I don't know the Sarnia area shops, but in London (about another hour from Sarnia) there is a really nice one called Joyce's Sewing Shop. It's on Wortley Road, in an area called Wortley Village. Very nice shop and a nice neighbourhood as well.
http://www.joycessewingshop.com/
This is the link to their shop. They have a special block for Canada 150 and they also carry many of the special Canada 150 fabrics as well as others.