These places carry Polish products in and around the DC area:
Taste of Europe, 630 Quince Orchard Rd, Gaithersburg MD, 301 590 9094
Phone: (301) 590-9094
(This is a store)
You can also get very authentic Polish foods at the Polish markets in Baltimore, MD. Here are some links and places:
Victor Ostrowski and Son -- 524 S. Washington Street, 410-327-8935
Polish garlic bologna, liver sausage, stuffed cabbage and horseradishes.
Polish Broadway Meats and Deli -- Broadway Market, Fells Point, 410-732-0972
Specializes in fresh country, Italian and Polish sausages.
Krakus Deli -- 1737 Fleet Street, 410-732-7533
Smoked meats and Polish sausages, jams, pickles, breads and herbs.
Sophia's Place -- Broadway Market, Fells Point, 410-342-6105
Polish delights, sausages, dill pickles and homemade sauerkraut pirogies.