My current theological crisis: Biblical authority

A few months ago I thought I had cleared up for myself how biblical authority 'worked'. The problem, it appeared to me, was to decide which meaning, of the many each text has, is God's word. This meaning I believed was the meaning for the original recipients (the fact this involved a good degree of research didn't bother me too much), from this authoritative meaning what God had to say to us was extrapolated understanding our own contexts and theirs noting the similarities and differences. However I have realised a number of problems with this. The less significant in my opinion is the fact that it is almost impossible to pin down the date of some of the OT books (something overlooked by me as my study has focused on the NT recently). Secondly I have remembered the early chapters of Genesis (thanks to Gordon Wenham). In the early chapters of Genesis the writer seems to be adopting sagas bashing around the near east at that time (Gilgamesh etc) and making them monotheist (plus a bit more). I always thought this quite a helpful discovery for preserving the doctrine of inerrancy but on further reflection I'm not so convinced. You have to ask what the author's thought process is here, and what he wishes to communicate to his readers. It all depends on what the Babylonians et al thought of their sagas; whether they believed them or not. If they did then the author of the Genesis 1 must have said to himself there is some obvious truth here but all this 'polytheistic stuff' cannot be right it must have happened like this... However (btw this is great as I seem to be working out my problem by writing it out which is almost the point of this blog) if the author of Gen was doing this it is hard to believe he (and his readers) held that the sagas were meant to be true, especially when he was so creative with the material he had (i.e. not just reducing the number of gods). A problem then arises though because as Wenham points out there are so many literary connections between Gen 1-11 and the Patriarchal narratives that if nobody believed Noah et al were real people then did they really believe in Abraham et al as well? To resolve this I really need to know more about the ancient near east's relationship to their sagas.I believe there is a book called 'Did the Greeks really believe their myths’; the same must be asked about the very different peoples of the ANE. I'll have to do some serious reading and quick because this is quite a serious existential issue for me.