For your First Saturday devotions

Sweet Heart of Mary, 

be thou my salvation

For more on First Saturday devotions: (thanks, Wikipedia!)

For more on Mary's role in our salvation:

• She uttered her yes "in the name of all human nature"
• "Being obedient she became the cause of salvation for herself and for the whole human race."
• Mary's role in the Church is inseparable from her union with Christ and flows directly from it. "This union of the mother with the Son in the work of salvation is made manifest from the time of Christ's virginal conception up to his death"
• For the first time in the plan of salvation and because his Spirit had prepared her, the Father found the dwelling place where his Son and his Spirit could dwell among men.

And find more here.