I lve in NYC, have a similar corgi - and I take her to work with me on the subway every day. This is the bag that we use:

http://www.amazon.com/Bergan-Signature-Comfort-Carrier-Ultramarine/dp/B005JUWC3E/ref=sr_1_3?s=pet-supplies&ie=UTF8&qid=1347883337&sr=1-3&keywords=bergan+comfort+carrier

Caveat: I unzip one end and fold down the flap so her head can peek out.