And I would suggest this, too : p It would be really really good to learn about Islam and what it teaches, so that you can talk to her about it, and help her understand how its wrong. In fact, I have three verses Id like to share with you here-
Quran 3:3-4 "He has revealed to you the book with truth, verifying that which is before it, and he revealed the torah and the Gosple aforetime, a guidance for mankind, and he revealed the criterion."
Quran 5:47 "Let the people of the Gospel judge by what allah hath reveled therein. If any do fail to judge by (the light of) what allah hath revealed, they are (no better than) those who rebel."
Quran 18:27 "And recite what has been revealed to you of the book of your lord, there is none who can alter his words; and you shall not find any refuge besides him"
According to these three verses, the word of allah cannot be changed by anyone. And the torah and the Gospel are from allah as well, and Christians are even commanded by allah to judge the quran against the Gospel. As Christians, we both know that the Gospel tells us that Christ was the Son of God who came to die for our sins : p If you can talk to her about things like this, I think it could totally be helpful. Definitely study up on the Bible and the quran, so that you can teach her how the two are not from the same God.