Answering Atheists: Who Created God?

After sharing the cosmological argument with the non-believer and explaining that the cause of the universe had to begin by an un-caused, timeless and space-less being with tremendous power. I would next say, since this being [which Christian's would call this being to be God] is outside of causation, outside of time and outside of space, this being had to be not only supernatural but eternal as well. (Then I would put the two together) Supernatural meaning outside and above our natural universe and since God is supernatural where he is beyond space and time that would make Him eternal. And since there is no causation, no space and no time before or with God then nothing had to come before God to create God. Then I would explain how consistent this is with the discovery of the big bang and in the Gospel of John. Then maybe bring up Augustine and how he understood the beginning of the universe, not by science but his study through the scriptures. Which was 1500 years ago and also is consistent with the discovery of the big bang.