You can try to find a good used pack on the island, or a cheap good used pack on the mainland, but then who would install it...? It's not that you have no options, just that none of them are easy - especially the cheaper ones. You could also look for a 'booster pack' for the existing battery, but then the installation comes up once again. You can try one more thing: run LeafSpy pro on the car, and if you have one or two bad cells, have the dealer replace just those, for maybe half the cost and less than half the range increase. Usually, though, the cells degrade evenly.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.