Passed up for promotion for less qualified employees?

I have been working in a government agency almost 13 years, speak fluently 2 other languages (Spanish and Portuguese) and every time I go to an interview I get rejected and people who are hired have started way after me and they are ALL Hispanics - I am not. What should I do? I feel totally discriminated - last one that got promoted was there for 4 years..another 6 years.