The cost effectiveness of conversion depends on several factors, including the cost to upgrade building systems internally and the external cost Con Ed may charge to bring in the gas line to your location. Upon receiving your info, my firm, Informa Energy, could easily do the price comparison based upon current rates. natural gas has been running at about half the price of oil for some time now, so there are definitely savings to be has in that respect.
The natural gas market hit a ten-year low in April 2012, but has been recovering ever since due to switchovers by large users from coal to gas as well as the unexpectedly hot summer creating increased demand for gas (which is used in generating electricity). However, the prices are still quite favorable and many of our customers have been opting to lock-in for multi-year terms to avoid rising rates. However, be wary of any firm offering to finance your conversion in exchange for locking-in for five years or more, as the markets simply aren't predictable over such a long period. You could lose the savings you'd otherwise enjoy. If Con Ed can't bring gas in anytime soon and you can't afford the conversion costs, it may make sense to burn 2 oil and wait.