Greek provisions in Brooklyn

Gack! I just had a salad with some supermarket feta
that was more like an industrial sealant than the
actual item. Whoever made that garbage and then
decided to label it as feta should be flogged. Can
somebody point me towards a place reasonably near to
Park Slope and decently provisioned with Greek food?
I used to live in Astoria so I know good places up
there, but I'm thinking of a place that I could make a
run to that wouldn't involve the BQE. My taste buds
thank you in advance.