Well, if you used TurboTax then you filed form 1040 which is not correct. Suggest you visit SprintTax/ a Tax professional/ school foreign student office for help in preparing an amended return --- you prepare using form 1040-NR and attach a note explaining that you made an error in filing form 1040 --attach a copy of the filed return -- mark on top that this is ONLY a COPY -- do not process. Assuming that you came in with F-1 either 2014 or alter , you are still within the exemption period.
I apologize for not making this clear -- since in your post you do say that you have used TurboTax ( just could not add 2 and 2 and make four --sorry)
