Naaji
God did tell us He was coming to earth in the form of a human. Please read Isaiah 9 and verse 6 "For unto us a child is born, unto us a son is given and the government shall be on his shoulders and notice the names this baby was given
Wonderful Counsellor, Mighty God, Everlasting Father, Prince of Peace
Now meet Jesus in the Quran and the titles given to him by your prophet
Surah 4:171 states He is "the messiah, Jesus son of Mary" That same passage calls him THE word of God. For Muslims the eternal word of God appear in the form of the Quran. For Christians, the eternal word of God came to earth in the form of the God-Man .. The Lord Jesus Christ. (John1:1-4,14) so both the Quran and the New Testament point to Jesus being the Word of God.
The Quran also refers to Jesus in more ways than just in calling him another prophet. He is referred to as Spirit, Prophet, Apostle, Preeminent One, Example, Sinless one and Miracle worker. Your prophet affirmed the virgin birth of Christ.
It is also interesting to note that you are taught that Isa will return to earth and that this unique demonstration of power and authority is reserved only for him.
The same descriptions of Jesus you point out in the New Testament are the words of men only... are also repeated in the Quran. Even the way Jesus was to die is repeated in both the Quran and the Old Testament. Surah 3:55, 5:17 and 19:33 all mention the death of Jeus. In Isaiah 53 the Old Testament prophet describes in detail the death of the annointed one of God and it's purpose. Many other such verses point this out.. without even looking for the New Testament realisation of such prophesies.
A final word on the place of the Injil (Gospels) and their crediblity can also be foun din Surah 5:72 "Oh people of the Book, ye have no ground to stand on, until ye observe the Taurat ( Law) and the Injil (Gospels) and that which hath been sent down to you from your Lord".
Now finally.. considering the question was.. what place Jesus and the Holy Spirit in the Godhead... Isa the Eternal Word of God says of Himself...
I am the Way, the Truth and the Life No man comes to the Father except through me (John 14:6)
and of the Holy Spirit and God the Father and their relationship to Him...
"Father, the time has come glorify Your Son, that your Son might glorify you.. ( John 17:1) and "this is eternal life.. that they may know you, the Only True God and Jesus Christ whom you have sent" ( John 17:3)