You've got a few problems. First is that the queue to get in this way is very long. You can check the priority dates here:
http://travel.state.gov/content/visa...checkdate.html

First off, none of these people are eligible to enter based on your green card. Once your fiancee marries you, then she becomes eligible. Your siblings (age is unimportant) and your parents are not. Only your spouse and unmarried children under 21 are eligible.