What is the expiation for touching various parts of a non-Muslim girl's body with lust, and what should be done to help her embrace Islam?

Touching a non-mahram (definition) woman is a grave sin, categorized as a form of zina (fornication/adultery) that does not necessitate a prescribed punishment (hadd). The perpetrator must repent, seek forgiveness from Allah, and increase good deeds. As for a girl's interest in Islam, this is commendable. She should refer to the Sharia (definition) body in her country to be introduced to Islam and its merits. It is preferable that this be done by knowledgeable Muslim women.