Secondly, continue to pray for them. Pray specifically that God would bring other Christians into their lives. Pray that the Lord would continue to show them his love in and through you. Pray that the Lord would use you to be a blessing to them and that God would protect you from the enemy while standing in the gap for your family.
Lastly, spend a lot of time alone with God, in prayer and studying the Bible. It is when we spend time alone with God that He can give us the strength to keep going even in the most difficult of circumstance. This time with God will not only strengthen you, but it will also give you a clearer picture of God's heart for your family and may even allow you to have the right words to speak at the time when your family would be ready to receive it.