I have to say I can't help you with an aethist sponsor, but do know that's one of the reasons that keeps me from actively seeking AA at this time. I've got to get over that hump, too. I'm somewhat of a Buddhist and don't necessarily believe in a diety, even though I still participate in wiccan and pagan rituals/events as well. It differs from the standard Judeo-Christian concept of God. There is no one who'll let you think of the higher power as yourself, your will, etc.?
If not, I think you'll have to move. Better to get yourself right, I think. Fight the good fight.