Milagros,
You've clearly articulated some tough barriers that are not easy to overcome. But, naming them is the start and now your challenge is to think creatively and, possibly, out of the box to make your way around the roadblocks. I like your idea of finding grads via other grads. Facebook is certainly a free option to finding your alumni. I know that some organizations who can't afford a designated alumni website create a Facebook Alumni page. You may be surprised how many of your grads "find you" rather than you looking for them.
June Gudeman