Awareness of Discrimintory Action

I have been working for a government subcontractor as a temporary since April of this year. Towards the end of May my supervisor decided to request that the position be made permanent and conqeuently it was posted on the internet. I applied for the position only to have him tell me that HR had contacted him (by phone) requesting that I lower my salary requirements. Since I had not been contacted by, nor have ever I met, anyone from the department I thought that the request was very unorthodox and decided to contact my agency. During my conversation with the office manager she informed me that I was not suppose to apply for the job, that if they were interested in hiring me that they would contact her to negotiate my wage, etc. Confused by all of this I told my supervisor that I was uncertain about incidents and the position altogether. He later told me that he withdrew the request to have the position filled. There were no interviews conducted and I have maintain my temp position.
Throughout my employment with this company I have (without question) endured verbal sexual harassment from my supervisor which I addressed a couple of weeks ago by telling him that the behavior was inappropriated and that further comments would result in a formal complaint. In retrospect I believe that he may have blocked me from employment by suggesting that I change my salary requirements, etc. Is it possible that I have been discriminated against without my knowledge?
It has also come to my attention that other temporary staff, working throught the same agency, have applied for and obtained permanent positions without any restraint from the temp agency. Can my temporary agency 'block' me from applying for permanent positions?