Break lease for bedbugs?

My fiancée and I moved into a new apartment together in May 2010.  Ever since, it has been a horrible experience with problem after problem.  In the first week at the new apartment, we had mice in the walls and ceiling of the apartment.  We discussed the problem with our apartment leasing office numerous times.  They brought in an exterminator and he came and examined the apartment and sealed cracks, set traps in the air vents etc.   We continued to have problems but were told there was not much else they could do since they were in the walls and not in the physical apartment.  The scratching was loud enough to keep me awake at night. 

As of right now, we haven’t had any scratching in the walls (but it occasionally comes back every now and then.)  We have a new problem now.  A few weeks ago, we found one bedbug crawling up the wall.  We were able to catch it and put it in a ziploc bag for evidence.  We went to the apartment manager yet again.  They had the same exterminator come back and spray our apartment.  There was no evidence of bedbugs in any of our bedding, sofa, clothes, etc… but we took the extra precaution and washed everything at a high heat, and began watching everything closely.  Then tonight (three weeks from the first spotting) I found another bedbug crawling up the wall.  I was also able to catch this one as evidence.  

Before I go and talk to the management yet again, is there any legal advice or any legal way I can get out of my year lease for these problems?  I have documented everything.  They have tried to remedy the problems, but yet they still persist.  

Desperate for a good night’s sleep……Please help!!