Why did you file a joint return ? You should have filed an injured spouse form if you were filing jointly ... but you can file one by mail now.
8379 is the Injured spouse form.
To file an injured spouse go to
Federal Taxes or Personal (for H&B version)
Other Tax Situations
Other Tax Forms
Miscellaneous Tax Forms - click the Start or Update button
7th item, Report an injured or innocent spouse claim
Here is a blank form 8379
http://www.irs.gov/pub/irs-pdf/f8379.pdf
And the 8379 instructions
http://www.irs.gov/instructions/i8379/ch01.html
Injured Spouse FAQ
https://ttlc.intuit.com/questions/1910698-form-8379-injured-spouse-allocation
