How do I get from the Ronkonkoma Station of the LIRR to Brooklyn without going all the way to Penn?

It is a possibility I will be going to the Brooklyn Botanical Gardens for the Home Grown event tomorrow and would like to cut out about a half hour of travel time by taking the train directly to Brooklyn. Otherwise, I would have to go all the way to Penn, take the subway to New Lots Station and walk from that stop. Any suggestions would be greatly appreciated! =)