I would look on her IMDB page to find her height. The only way you would be able to find her measurements is if her resume was floating around on line. Which is very unlikely.
I think it's either William Morris agency http://www.filmreference.com/Actors-and-Actresses-Ro-Sc/Sarandon-Susan.html Or ICM http://famous-relationships.topsynergy.com/Susan_Sarandon/Contact.asp