This month the manual states to pick a song of your choice from the Children's Songbook.
April's Theme is:
Jesus Christ is my Savior and Redeemer
Week 1: Jesus Christ was chosen to be our Savior.
Week 2: Jesus Christ is the perfect example for us.
Week 3: Through the Atonement of Christ all mankind may be saved.
Week 4: Jesus Christ was resurrected and I will be too.
I think just about any song about Jesus Christ is appropriate for this month.
A few suggestions might be:
I Feel My Savior's Love
I'm Trying to Be Like Jesus
Before I Take the Sacrament