If my priority date is 1 January 2007 in F4 category, how much longer will it take?

More information is needed. What country are you from? Is your spouse, if you have one, a citizen of another country? These questions make a difference, because certain countries have overextended themselves and applicants from those countries must wait longer. As a result, I strongly recommend an appointment or teleconference with a competent and experienced immigration attorney before matters get more complicated. The above is general information, not legal advice, and does not create an attorney client relationship.