How Long After Stopping Depo Provera Can Periods Restart?

Hi, I had my last Depo-prov shot in late Sept. 2010 after being on it for 4 years, durning this time I never had periods and assuming wasnt ovulating. Now that I am trying get pregnant, I have yet to start my period again-after how long should I expect to regain my fertility? Would provera be an option?

Thanks,

Shi

29 yrs mother of one 4yr old child-