My DD was born at 34 weeks. She was 4lbs and 3oz at birth. She was on a vent and oxygen for a few days and she was under bili lights for about a week. The only thing she needed to do before going home is learn how to consistently eat from a bottle. There was no certain weight that she had to be, just as long as she could eat well. She was really pretty healthy, just little.
If you have your baby now, your chances should be pretty good! Congratulations to you!