I have H1B visa (my wife and my daughter have H4) and i would like to change it to green card, My sponsor would like to do so as well.

My visa is valid for 3 years and could be extended for another three years (first 3 years started from october 2005 - september 2008).

When can i stard changing that - can i apply for the green card on the first year or should i wait for some more time?