Paid less tax for ay2014-15

For FY 13-14 ie AY14-15 . I earned 428000 of which 19200 was paid as TDS. At the time I did not file any return assuming I had no tax liability . But later I realized I have to pay another 2800. I am a student who usually makes bellow the income tax bracket so I haven't filed any returns. As I understand I cannot correct this as returns can be filed only upto previous 2 years. I haven't recieved any notice.How can I pay now and what would be the penalty? Will it cause any problem later on if ignored?