Landlord and maintenance fail to fix issues, what are my options?

I have been living in my current apartment for 5 years. The property is regulated by HUD. For the past 2 years we have had to deal with a major problem with cokroaches. This problem has gotten significantly worse. We schedue monthly exterminations with the office, but they cancel about 40% of the time and it has to wait untill the next month. We have contacted them about repairs needed and these have gone unanswered for 8 months now. I have recently found a newe place and my move in is the 15th of this month. I was unable to give a 30 day notice. I guess my real question is, What are my rights? and do I even have a leg to stand on if this gets nasty and ends up in court? Personally I dont feel I owe anything for the conditions of the place, but I would like some answers from people with more expierence with the issue. Thanks for any help.