In the 17-1800s it was common for slaves to be given Christian names (as their owners wanted them to be Christian and to forget Africa) and it was also common that a slave would take the last name of the person who owned them. That way you always knew who that slave belonged to (and in many cases may have been fathered by).
Most slaves brought to the U.S. were from the West coast of Africa, once called the Slave Coast. The regions today are Nigeria, Ghana, Togo, Liberia and Sierra Leone. It is probably impossible (or would take an enormous amount of research and luck) to find out which particular region your ancestors originally came from, as slaves were stripped not only of their social and cultural status, but of their African names and background as well. African names, religion, customs and heritage were actively discouraged by Anglo American christians who considered it 'savage and barbarous'.
Most of the Africans who were brought to the New World were from 3-4 major ethnic groups in West Africa: They included the Yoruba (Nigeria), the Fon, the Ebo, the Hausa, the Fulani and the Ashanti. Hausa and Fulani of Northern Nigeria (then the Kingdom of Oyo) were Muslims, while the others had their own indigenous faiths, of which the New World form of Vodoun (Voodoo) is derived.
Don't get completely stuck on your African heritage - one in three African Americans has Native American heritage as well, as slaves often married with - or in some cases escaped to - Indian tribes. Masters also had children with female slaves, adding Caucasian heritage as well. In that sense African Americans are more truly American than most European Americans because they are a real product of the racial, ethnic melting pot here.
Keep digging into your past - ask your older relatives as much as you can and try to get them to tell you the 'real' story - even the stuff 'people don't talk about much' as that can give you clues too. Find out where in Georgia your ancestors may have been slaves - look for Swint plantations there. There are many resources for the unique challenges African American geneology poses - and many of them are on the internet.