Of course he can "request" it -- but I doubt Obama has much left in his "stash" after paying for food stamps and Obamaphones and stuff.
Christie isn't going to get anything near that amount, and he knows it!
BTW I believe the Federal Flood Insurance program only covers up to a maximum of $250k + $100k contents for a home or $500k for a business. Since the bad damage was mostly due to storm surge flooding, a lot of homeowners and businesses have big uninsured losses after Sandy. The FEMA low-interest loans probably aren't such a bad deal if someone was planning on a teardown anyway -- otherwise, not. And most weren't.
Unprepared Government and Graffe