Salary range in Long Island, NY

I still haven't got the offer yet (not even on-site interviewed, just felt they are very interested in my experience), but the department hiring manager kept asking me about my salary requirement without giving me their salary range. It's a senior level supporting IT staff position in a college. I checked the living cost there, way much higher than my current city. I know I'm not supposed to give out my number first before getting the offer after reading the posts here, but what number is a reasonable number any way? Any idea? Many thanks for your suggestions.