Family Based Greencard

CASE BACKGROUND: I HAVE BEEN INTERVIEWED FOR ADJUSTMENT OF STATUS PETITION ON DEC 12TH, 2003 AT GARDEN CITY. THIS CASE WAS FILED BY MY U.S. CITIZEN MOTHER. IT WAS FILED WAY BACK WHEN MY MOTHER GOT HER GREEN CARD UNDER THE CATEGORY UNMARRIED SON OF PERMANENT RESIDENT.MY PRIORITY DATE WAS NOV 3, 1994 THAN. I CAME TO THIS COUNTRY ON B1/B2 VISA AND AT THE SAME TIME MY MOTHER BECAME US CITIZEN, THUS WE FILED ADJUSTMENT OF STATUS. CURRENTLY: I'M WAITING FOR MY GREEN CARD AFTER THE INTERVIEW. QUESTION: 1. I KNOW A GIRL WHO IS OVER F1 VISA HERE IN NY. SOME ONE SUGGESTED US THAT IF WE GET MARRIED AND FILES HER PAPERS AT THIS TIME(BEFORE I GET THE GREEN CARD) WE BOTH CAN GET IT TOGETHER AT THE SAME TIME. I DON'T KNOW IF ITS TRUE? 2. IF ITS TRUE HOW THE THINGS WILL WORK OUT FOR ME. I MEAN ACCORDING TO THE IMMIGRATION OFFICER..IT COULD TAKE SIX-EIGHT MONHTS AS THE THINGS ARE GOING ...BUT IN THE ABOVE SITUATION IS THAT GOING TO TAKE LONGER THAN THIS FOR ME. I JUST WANTED TO MAKE SURE BEFORE I GO AHEAD AND TAKE SOME STEP.TIME FRAME IS REALLY IMPORTANT. IF ANSWER TO QUESTION NUMBER 1 IS AFFIRMATIVE AND U CAN GIVE ME THE APPROXIMATE TIME PERIOD AS ASKED IN QUESTION 2