My mother was Helen Chepurny, but not in Canada. One problem you will have is the continuous alteration of spellings of the last name. I've seen spellings like Czepurnyj, Tschepurnyj and others on papers I've seen through the years. So - the same spelling of Chepurny may actually be quite meaningless. Sorry, but you're facing the same dilemma in ancestry search that I've found.