The Bible is quite clear on this. Acts tells us :
"let it be known to all of you and to all the people of Israel that by the name of Jesus Christ of Nazareth, whom you crucified, whom God raised from the dead--by him this man is standing before you well. This Jesus is the stone that was rejected by you, the builders, which has become the cornerstone. And there is salvation in no one else, for there is no other name under heaven given among men by which we must be saved." (Act 4:10-12)
Jesus is the only way to salvation. If anyone dies without confessing him as their Lord and Savior, they will not be saved.
Whether or not there is a future plan for Israel depends on how you view the scriptures. Just remember what paul said to the Galatians:
"Now before faith came, we were held captive under the law, imprisoned until the coming faith would be revealed. So then, the law was our guardian until Christ came, in order that we might be justified by faith. But now that faith has come, we are no longer under a guardian, for in Christ Jesus you are all sons of God, through faith. For as many of you as were baptized into Christ have put on Christ. There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female, for you are all one in Christ Jesus. And if you are Christ's, then you are Abraham's offspring, heirs according to promise." (Gal 3:23-29)