Notice under 143(1)

Hi,

I got a notice from IT Depatment. under 143(1). I dint disclose my income on which TDS was deducted. But took the tax credit and filed the ITR claiming refund. It was obvious that the notice was going to be issued. Now i could not revise the return as it is a belated return. So, my Ques is

1. What should i do- simply file rectification under 154. 

2. If i File. Does it will attract any interest and penalty?

3. Can I also show any extra income which i hav not been written in Notice.- and what will be its affect if i show  it.

Thanks in Advance !!!