I lived in that area for a while; I had the best success with marigolds, "Autumn Beauty" sunflowers, delphiniums, daylilies, hostas, peonies, black eyed susan, foxglove, daisies, crocus, red japanese maple, pines, and so on. It can go between zones 4-5, depending on the weather. It also rains quite a bit, usually....
I forget the name of the garden center, but there was a good one on Upper Front St. in Bingahamton, NY. It was exit 6 off of I-81, make a left at the bottom of the ramp. There is also a Lowe's in Vestal...Hope this helps!