If you hear an air-rushing sound, it's almost certainly due to reed strength, as you are finding out. Leaks in pads or body joints are more likely to produce squeaky notes, or make it difficult/impossible to play notes which expect the given pad to be closed.
But far more important: please take some lessons from a qualified instructor. It's all too likely that you are using the wrong embouchure (sp) in an attempt to compensate for lack of breath control. While picking a proper reed strength is a good idea, the last thing you want is to pick up bad muscle habits. They're very difficult to cure.