It might be best to start with the St Michael's cemetery records - try to get a birthdate from her stone or from their records and any additional names for Violet ie a middle name and maiden name. If they don't have anything more then you will need to get her death registration info from Ontario Vital Statistics using her death date.
From your tree at ancestry it appears Violet was James BRADSHAW's 2nd wife having married him sometime after his 1st wife Ethel Maude MacDonald died on 3 May 1949. Violet's marriage to James likely recorded her maiden name and parents names but you need a marriage date to get her marriage record from Vital Statistics and marriage records are not available for public viewing for 1949 yet.
Her obituary might help as well - likely was in a Cobourg Newspaper.- Mary