Salaam,
Carol my friend let me clarify something to you. When the verse talks about the books of the peopel before you, God is referring to the Gospel of Jesus ( the Injil) and the Torah. However what you have today is not the Gospel of Jesus, but the Gospels of Mark, Luke , Matthew , and John. The entire Bible is an encyclopedia of many Books in which we Muslims do not accept as the Word of God. I don't know if you already know this, but we Muslims are told that the God had revealed to Mankind many Holy Books before the Quran, such as the Gospel of Jesus, the Psalms of David and the Torah of Moses. There were others but these are the 4 main ones.
I hope you understand.
Peace be to the believers