Anne,
You should be able to buy them at most any large boating store, West marine, Armchair Sailor, etc. I am looking at a nice Canadian chart of the Gulf Islands in a small enough scale to see all of the islands on one sheet. The chart is either #86 or #98, the way they have the numbers makes it unclear. You should also find your chartplotter chart chip goes all the way up there and quite a ways beyond. There is a large chartbook #3313 published by Canada that covers all the Gulf Islands. See you at Nanaimo.