Whats other ways to get a 410 probation off your record other than waiting the 5 years after the probation?

I was given 1410 or 410 probation in 2004 for possesion for a wrongful arrest that I should have never been arrested for but because I did not have 3000 dollars for an attorney retainer fee the public defender told me to take the conviction & it would be expunged after 2 years not 5, but I was recently told 5 years. The probation was terminated in 2006 in excellent terms but now that I found out I have to wait 5 years I want to know what advice can be given to get this off my record or what law firms in chicago work with wrongful convictions?