Hm, well when I have writers block I usually try and think about where I want the story to go. You could write down all the ideas you have for the story, all the things you want to happen, even if its just a brief outline, and then try and work out how to get there. That's usually how I write, because I have a lot of ideas first, and then try and think up how to get to that point. Then once you have those ideas written down, and have worked out how you're going to get there, you should be able to write again :)