Salaamalaykum sister alf2,
You can eat your predawn meal right up until it is time for call to prayer (adhaan) for Fajr prayer. It is NOT Fajr Iqama and also NOT Sunrise.
(Iqama is the time when the people pray in congregation at the mosque or a prayer hall. This time is after the Adhaan.)
Please go here :-
http://www.islamicfinder.org/cityPrayerNew.php?country=usa
Enter the name of your city & look at the time for Fajr Adhaan. You can not drink or eat beyond this time. You should complete your meal and drink and rinse you mouth clean before this time.
Also these times change from day to day by a minute or two. So make sure you either save the entire month's schedule on your PC or print it out, so that you have it handy everyday, sister.
PS .. It says 5:43 am for Fajr Adhaan in Atlanta Georgia for Today 11th August. Maghrib it says 8:29 pm. That's when you break your fast, sister.
The site seems to have problems loading. Perhaps due to high traffic. InshaAllah it works for you.
Please keep asking any questions, confusions, doubts etc etc.
Wasalaamalaykum waa rahmatullahi