Yes. You will need to file an amended return to account for the income. Any tax preparer can help you with this. If you feel confidant about doing it yourself and saving yourself some money, you can visit the irs.gov website and get form 1040X. This is the form that you need.
Don't forget that you will need to amend your state return and any schedules that you originally filed as well.
Let me know if you still have questions.