Do people survive the first stage of leukemia?

MY girl friend was recently diagnosed with leukemia and doctors told that she was in first stage. I am really depressed and I really want to learn more about it. Doctors told her that it was a acute leukemia. Will she be cured? Doctors also said that the blood has grouped on the left part of her head. She is very weak. Her mom died when she was 3 months old she didn't grow up fed and she catches diseases easily. She has low immunity power. I am really scared and don't know what to do. Doctors are saying there is not much to worry about since its in first stage and its gets cured. I have been following up with the web sites and they usually show up the five year survival rate. What do u mean by the survival rate for five year? Does that mean people only live for five years? Please let me know and thank you!