You need to find some local startup / entrepreneurship community and meet some people. You are definitely not ready to be approaching investors now, so don't worry about that at this point. It's not hard to raise money when you have the right idea in the right stage.

Forget that about somebody stealing your idea. That simply doesn't happen. You know, I had software with basically same features as the first version of Twitter at least 6 months before Twitter appeared. And look were Twitter is today, my software is definitely not. And I'm not sorry because I'm well aware how things work. It's not the idea that counts, it's all together, the complete process, people and product, every single thing counts, idea is just a tiny, tiny part of it all. There were some cases in history where idea was everything, but they are so rare that you can easily consider them to be statistical errors.