what is the starting date to apply for H1B visa?

hi, currently i am on dependent(F-2) visa and i have done certification course in accounting in USA and one of accounting firm is ready to hire me on H1b visa. So when and how will i get the H1b visa for this year because the quota for 2012 is already finished in june and for 2013 can the employer apply in October 2012? Can i start working from January 2013.

Like you said the cap for this year is closed. The earliest you can apply for the next years cap is Apr 1,2013 and you can only start working beginning Oct 1,2013. Your only option of working before that would be to look for a cap exempt employer like a University/Non profit Org.