There's no need to buy "cycling specific" clothing. I used to commute from Prospect Heights to the Upper West Side in regular clothes, albeit in layers I can peel off along the way. Even in the dead of winter, I would be burning up by the time I got to the Manhattan bridge and would have to take my mid-layer (usually a sweater or hoodie) off and stick it in my pannier. Only "special" accessories I would recommend is a face mask/baclava and Goggles. Keeping your head warm goes a long way.