Actually, you stumbled upon a Intra-Christian discussion regarding the hermanutical approach to biblical prophecy.(i.e. covenantial v. dispensational theology) However, that does not preclude you from the discussion. I would suggest that your responses would bear on the article above and frame your arguments based on any scholarly independent sources. Perhaps you know of some Islamic apologetics that refute the cogent agruements presented in the article?
Here's your challenge.
Present some evidence that the Bible is not consistently pointing to Jesus Christ as the Redeemer for the sin of man. Present any evidence that Jesus Christ is only a prophet and not the Saviour.
Present some evidence that the Koran, as an extra revelational book, is confirmed in the Bible.
Present some evidence against the Trinity. When presenting evidence do not use the Koran as your proof unless you can prove that the Koran is a God-inspired extra revelational book.
One other point. I affirm absolutely the right of any person to practice the faith of their choice as long as they obey the laws of this country. However, the tone of your arguement (and it seems the arguement of most Muslems) seems to suggest that we should accept your faith intellectually because of your belief in the Bible. This is a faulty premise. Most Christians do not accept the faith of Mormons as true faith for the exact reason we do not accept Islam, that is, extra-revelational books.