It is unfortunate that they are no longer on that campus.
I recommend contacting the university to see if they have any records of ANYTHING pertaining to the organization or some of the members whose names you remember.
I assume it was a local so there wouldn't be a larger entity to contact. (There's another Sigma Phi Nu that was founded in 1996)
"When Will Jesus Bring the Pork Chops?” This title offends all three major religions, and even vegetarians!"~ George Carlin
"Ever notice that anyone going slower than you is an idiot, but anyone going faster is a maniac?" ~ George Carlin