Yes, you can file an injured spouse claim to get your portion of the joint tax refund for a prior year tax return that has already been filed, as long as you meet the definition of an injured spouse. Please review these requirements on page 1 of the IRS instructions for the injured spouse claim form, under the heading, "are you an injured spouse?". https://www.irs.gov/pub/irs-pdf/i8379.pdf. 

Please note that it is NOT necessary to amend your tax return in order to submit the claim. 

Please refer to page 1 of the IRS instructions for the injured spouse claim form, under the heading, "when to file", for details regarding the deadline for submitting this claim. 

You may be able to complete this form in Turbo Tax but you will need to print and mail the form to the IRS. Please refer to page 1 of the IRS instructions for the injured spouse claim, under the heading, "where to file", for instructions regarding where to mail the form. 

Please refer to the following FAQ and click on "what if I've already filed my tax return?", to learn more about how to complete this form through Turbo Tax. https://ttlc.intuit.com/replies/3326788