If you watch much court tv you'll find that in the Utopian Republic of Canuckistan the max you can get for your most henious multiple or serial murder conviction is 25 years in country club comfort. Hell these two will have plenty of time after they get out to get back together and move next door in sunny Dania Beach Florida and while still living off the Canuckee dole.
Not strictly true - the crown can move to have you declared a dangerous offender, which allows them to be kept in prison indefinitely, until it can be proven that they are no longer a risk. See Paul Bernardo, for example.
OTOH, since the girl in this case is 12 years old she's too young to be eligible to be tried as an adult and the maximum possible penalty she faces is 10 years. Don't know if young offenders can be declared dangerous offenders, although even if so it's probably pretty unlikely.