If you can stay sober and transform your life on your own resources (intelligence + willpower), good luck to you!
If you can't, it's either curtains, or there's a solution.
If there's a solution, by definition that solution involves a power greater than your own resources (intelligence + willpower).
If you're sober a while in AA and your life is transforming, that higher power is, by definition, operative already. This isn't a matter of belief or faith; it's a matter of observation.
If it's not yet transforming, are you applying the Steps? This is a known method of invoking and activating that higher power. Complete that process, then revisit the considerations above.
Do I need to believe in God? No, because you're asked whether or not to believe in and try to seek a higher power (see above). That may or may not be God. Or it may be the transformative power of human goodness acting in concert. You get to pick.
Do I need to be bothered by other people talking about God? No, because other people get to pick, too, and they've picked God.
Are people ramming God down my throat in AA? Maybe. Or maybe they're just talking about God in their lives, and you're taking it personally. If it's the latter, get over it: they're just talking about themselves. It's not all about you.
If it's the former, well maybe they just haven't learned boundaries yet. Once they've gone to a few Al-Anon meetings, they'll stop assuming that their way is the only way.
Do I have to go to a separate group for agnostics and atheists, if I don't believe in God? No, no more than Buddhists, Christians, Jews, or Muslims need their own group to preserve them from people of other or no religion. Your higher power might be a hitherto unexpected inner resource, the strength of AA as a whole, the power of collective knowledge and experience, the comfort of the group, or something entirely undefinable.
But I find it so hard to listen to people talking about God! Then you have some great material for your Step Four, and some great opportunities to learn the very human virtues of patience, tolerance, kindness, and love. Religious people have to get over the fact that many atheists and agnostics can and do get well without a conception of or belief in a traditional god. The same applies in reverse.
That's exactly what AA is about: unity does not mean uniformity; tolerance means letting other people be different or wrong, and sometimes ultimately more right than we would have cared to admit, and that goes for everyone, believer or not.