Since you could not deduct the contribution you now have basis in the IRA and you should have a form 8606 from that tax year that you will need to use to complete this year's return. If this is the only IRA you have and you cashed it out completely then you will only pay taxes on the earnings plus a penalty for early withdrawal if you are not yet 59.5 years old.
All you need to do is enter the form 1099-R issued to you by the IRA and complete the follow up screens to enter the basis from the form 8606 as directed.
