I want long hair, but how?

I have shoulder length, blonde, curly hair. My hair hasn't grown over the past four years, well it has but I keep straightening it so much that my hair just breaks off the ends and stays the same length. I've stopped straightening it, or at least reduced it to once every two weeks, but my hair keeps breaking off! I want to have long hair but I can't grow it when my hair is like this. Can I get real hair extensions that I can straighten and they will go back to curly again? What is the solution to this never ending problem!? I am really killing myself here, I WANT LONG LUSCIOUS HAIR!! Ahhhh help me please.