You will have to wait until the IRS processes your return and sends you the refund if you are getting one. Then you can prepare, print, sign and mail an amended return form 1040X to add the income omitted from your original return. The 1040X will probably not be available in TurboTax until late February or March. Do not make any changes to your original tax return until the 1040X is available and you can start the amending process. The 1040X must be printed and mailed. It can't be efiled. The IRS can take up to 16 weeks to process a 1040X.