About God(s?)

In many of the fantasy books I read there is more than one God, sometimes the Gods even work together, or consults with one another, when ruling their worlds. I started to think about this and wonder how it fits in with LDS doctrine. A saying often used in the church comes to mind, "As Man is, God once was - as God is, man may become." The belief is also that God is never ending. So - If God was once a man, He must have had a God. What happened to that God? Is He still ruling a world somewhere? If we are to become Gods (or Goddesses) our present God will still exist . . .right? How does this fit in with the belief that there is only one God? Does it mean one God for this world, or universe only? Is space, which is endless i suppose, filled with other worlds, universes, Gods? If not how will we, in turn, become Gods? If we do become Gods, will be still be accountable to our God?