Discount Armageddon by Seanan McGuire

Discount Armageddon is the story of Verity Price, a blonde twenty-something cryptozoologist and recent transplant to New York City. She pays the bills by working as a waitress in a strip club, supports the family business by working to help the local populations of cryptids – monsters to the unenlightened – and secretly dreams of making it big on the ballroom dancing competition circuit. She hates public transportation, instead getting around by running parkour-style across the city rooftops, all while armed to the teeth with every kind of weapon she can hide under her skimpy waitress uniform. Oh, and her roommates are a colony of talking mice that venerate her every act with religious celebrations and feasts.