Interesting storyline. Instead of Harry going back, it's Ginny. Nice idea. But if Ginny is the special one, is it going to be her and not Harry to defeat Voldie?
Ginny is special indeed. However the prophecy still states Harry is the one to kill Voldy or get killed by him. Now, the Harry from the other world died at Voldemort's hand fullfilling the prophecy. Whatever happens in this world, however, we don't know yet, but I'm sure Ginny will do everything she can to make sure he survives.