What more do I need to prove Retaliation against me by my employer?

I been at the company almost 5 years as of 9/18/11. It started when I went to upper managment in another state about the treatment the call center employees were getting in my building. Soon after, I was pulled into a room by my supervisor at that time and she adsked me, "Why did you do that, now everyone is upset with you?" And she said, "You will never be able to move up like that" So, here we are, 3 1/2 to gour years later, I am still in the same position after applying for possibly 15 openings. I have over 200 pages of proof where I have applied,been denied, tried, and been fried, after they lied telling me why I didn't get the positions. I have sat (shadowed)with other employees before work and during lunch trying to learn more about the positions before I interview and it has gotten me nothing. Today I got wrote up for my performance which really makes me feel like they want to fire me or I leave the company but I feel I have been put on the "Black List" and I will not be able to advance since I so-call blew the whistle. I am so frustrated, discusted, discouraged, tired, emotional, and I want to bring a lawsuit against them before I leave because other people have left for this reason and noone has pursued legal action against them. I need help, my money is low, and I can't afford a lawyer right now, but I have a very, very, strong case. What should I do and how can MEL help me?