To say that non-Christians can't go to Heaven is extremely presumptuous.
Who are we to dictate what God can and cannot do?
As a Christian, one may have beliefs as to who is more likely to go to Heaven, and what one must do to get to Heaven, but in the end God can do anything He wants to.
That includes saving a non-Christian.
So why not quit worry about who's NOT going to Heaven and start thinking about the fact that God can zap you for being a jerk if He feels like it.