Mohammed,
Gene therapy as an available cure is still years away. Currently the only cure is bone marrow transplant (BMT). Success rates have climbed with BMT, with a higher than 90% success rate in many of the BMT centers in the west. However, a matching donor is needed.
Treatment for thalassemia has improved tremendously in the past two decades. It is no longer a death sentence, but has become a manageable chronic condition. Please learn as much as you can from our site about managing the care of a thal in today's world.
I realize that it is hard to accept this reality, but for your child's sake, you cannot dwell on this. Your job is to be the best father you can be to your daughter and fully accept everything about her, including this genetic disorder. One thing I learned from observing the eminent Dr Eliot Vichinsky, one of the world's leading thalassemia specialists is that parents often are so absorbed in what is wrong with their child and overcoming it, that they forget some of the simple things about being a parent. Please make sure your bond with your child is strong and that she gets all the special love you have to give. This is just as important as any doctor or treatment you can find.