Do I have a valid case of employment discrimination?

I have been employed at a Healthcare Billing company for over 1 year. At the time of my hire, I was told by the Hiring Supervisor that there was much room for growth for a person with the level of experience that I possess. With this in mind, I went above and beyond to prove my worth equitable in the company. The first thing that caught my attention was that my web-based resume was yielding Supervisory Jobs from the firm that I am employed by; however they were not first internally advertised. When I went to HR to report this..I was told that "yes, that this was a position that was in need to be filled, however it has not been offered to the existing staff, because the applicant must possess certain qualifications" Although I knew that I had the skills, I accepted this answer. Over time, I initiated many proposal based meetings with the existing leadership team in an effort to show my skills valuable, and offered suggestions to our existing policies; however to no avail. I provided a job description of a "Proposed Research Coordinator" position, but was told by HR manager that if the decision was made to implement the proposed position that it was possible that "I do not have the skill set to fill it." Let me say this, I have a 8 year proven track record in all functions of Healthcare Billing, and have maintained the status of Top Producer in my department from my direct supervisors. There have been supervisory positions advertised since then; however on all 3 occasions outside white employees were hired to fill these positions, without even interviewing the internal applicants. When I confronted the leadership team, each employee that was hired was forced to resign for "misunderstandings", and were paid considerably well for their time. Since then, no supervisory positions have been filled, and the one African-American Supervisor that was there, was forced to quit due to discrimination from Billing Manager. Since her departure, two of the white applicants to the "Collections Supervisor" position have been assigned to temporarily take over her duties to include: employee evaluations. There has also been talk of a supervisor position for the department that I directly work for; however when I questioned the HR team about when it will become available "Management has not decided if the position is needed yet". However, prior to internally advertising the position that was to become available in my department, I was told by Billing Manager that she had already offered the position to a sister of an existing white employee. (One of the same that are now temp filling duties of previous Ass. Billing Manager). As you can probably tell, I became a nuisance to my employer--so in effort to shut me up--They put me on a Sub-compliance committee to formulate our corporation's first compliance manual. At first I thought that this was leading to something until my Billing Manager asked me if I would consider moving to an entry level position so that I could sit right outside her office, and she could give me special projects, and monitor my progress. What an insult. I told her that I would not move anywhere especially to make room for a white outside employee that she had already offered the position to. Upon reviewing documents for MY NEW SUB-COMMITTEE, I found a job description for the Supervisor position in my department, and GUESS WHAT? It actually showed the date that it was created, which was around or about the time that the outside white employee was offered the position, and around the time that I was asked to move into an entry level position. I am almost willing to bet my life that she was offerd the position of "Supervisor"; however the only thing that was advertised to internal applicants was a Team Member position. Thus excluding me since I already worked in the department. The only promotions that have gone on are lateral moves for black employees, and as of now all management personnel consist of white employees. I still have never received an interview for any of the positions, and have watched underqualifying white employees get promoted. I have filed a Charge of Discrimination w/EEOC, and have requested a personal leave of absence from my employer in writing due to the acts of discrimination. I have documented all contact with them since the beginning of my employment, reviewed my HR file to find out if they was anything in there preventing my promotion that I did not know about, and found no documented reasons. I have tried on numerous occasions to bring this to my employer's attention; however I was told that I was impatient, and angry. I have been subjected to discriminatory treatment by the firm for allowing such actions to take place, and for covering up all acts of discrimination. I have been a victim of "rude and discriminatory" comments from my Team of Supervisors, and I do not appreciate it. Please help me....They have been charged with this same thing before, however the plaintiff settled out of court...What can I do to make sure that this company learns from the effects of their illegal discrimination?