If the zone was changed to more severe flood zone and the base elevation is not at that height then the insurance will rise unless you raise the home.
Almost all homes in the USA qualify for flood insurance through FEMA with 2 exceptions and they are very remote places I never heard of. The problem is the premiums for houses that are not at the base flood elevations mandated by the FEMA charts. The highest premium could be $31,000 but that is in areas where homes were completely devastated.
There are charts to show the base elevations on the new FEMA maps
go to http://www.region2coastal.com/sandy/table
This home had a Base 'Flood Elevation of 6 feet before the new advisory maps. This home was probably paying a small premium because it appears to be lower than 6 ft elevation from the picture.
The new advisory maps(which are not mandated yet but probably in 2013-14) show a ABFE of 10 feet. Meaning if Lavalette enforces the new advisory maps then you will need to either raise your home to 10 feet or pay a higher insurance premium. Oh and watch the height restrictions!! When you raise your home be careful not to go past height restrictions.
Good news is FEMA is giving up to $30,000 for primary homeowners to raise their house if they qualify. Bad news is trying to find a company to do it for that price.
Hope this helps
If you are not working with an agent give me a call and I can assist you.