citizenship/conviction

I am a permanent resident since 08/2000. In 2004 I was arrested for theft and received a misdemeanor and 2 yrs supervision which was discharged on 7/30/06. This is my only offence. In 2005 I applied for citizenship, but because I was still under supervision, it was denied. I received a letter, saying to re-apply in 2009 (5 years from the arrest). On 7/28/2009 it's been 5 years since the arrest. However, I was told that I have to wait five years since my supervision ended, which would mean that I could apply in 2011. Also, I was told to expunge my record before applying for citizenship. My green card expires 8/2010. What should I do? I appreciate all the help! Thank you