I second (third? fourth?
) what others have said on this subject. Find out if other members of your sorority have transferred to your new school (from anywhere - not just your old school) and are interested in starting a chapter there; that will give you a group to start with. Then, petition the campus Panhellenic to bring your sorority to campus. If they refuse, start a local sorority - either with the goal of ultimately becoming part of your NPC sorority, or with the goal of staying local.
Good luck!