You can find an attorney through various organizations that can tell you if your case has merit, and what to do. Since you left at the landlord's request, however, that changes the dynamic of the situation, so I would talk to a lawyer before paying her another dime. The Bar Association referral service on this page:
http://www.housingnyc.com/html/resources/legal2.html can help you to find an affordable lawyer, and offer an inexpensive consultation service.