http://www.dirtdoctor.com/view_question.php?id=94 should be a good resource for you. Fire ants do not like biologically active soil. The soil must be in good health to grow healthy plants. Far as the weeds, it depends on what kind of weeds they are. Weeds grow in places that are bare. If you have bare soil, mother nature will put something there for you.
Also, this discussion board has many different sections or forums. There is a part about fruits, vegetables and herbs, a part to find out about events, etc. (Gardener Exchange), a part about weeds (Weeds), etc. This particular forum is about how to use the discussion board. Obviously, you are not the first one to post a garden question here, but I think you would find this discussion board more helpful by utilizing specific forums.
Oh! Hopefully bermuda grass is not what you tilled under. If you have bermuda nearby, you will need to do a raised bed or put a 4 foot tall barrier between the bermuda and the garden. (Maybe I exaggerate a
little).