You can amend your tax return and add the vehicle's property tax and sales tax as a deduction. However, if you didn't itemize: had mortgage interest, real estate, charitable donations, state income tax withheld - the new car deductions may not make a difference on your tax return.
Here are amending instructions just in case: https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed