CALL YOUR UTILITY COMPANY. They may have a low interest rate loan available for this purpose. They may have a list of vendors, you can get estimates from. I used the "Borrow to Benefit" program some years ago for the conversion of a split level from electric to gas. It was a very low rate and up to 10 years to pay (always pay off early if possible). Good luck.
Wish I could help with but i'm a no go on this. I'm assuming you have tried all standard avenues; your Northgate management people, LIPA customer service, the Grid customer service...etc. Possibly the town government guys could provide some input. Good Luck. The statement; 'cost from someone who has actually done it '. is a stopper for me.