NYC $165 parking ticket for blocking a pedestian ramp? HELP PLEASE!?

I live in Staten Island, New York. I recivered a $165 parking ticket for blocking a pedestian ramp. I was in cl at St. John's university taking my last exam of the year. When I finished I went to my car and saw I had a ticket on my windshield for blocking a pedestrian ramp. I did not see the ramp. I cannot afford to pay such an expensive ticket. Can someone give me advice on what to do?