Itemized. If you are married, then you have two options. You can file "Married Filing Jointly" or "Married Filing Separately." You cannot both file Single.
Your prior-year tax returns should both be amended for the federal and state returns. It is not allowed for you both to file single when you are married. It will cause you more problems to not fix your prior year's tax return as soon as possible.
The rules are different depending on the filing status. Your best bet is to amend last year's return and with the filing status of "Married Filing Joint."
If you are not sure what filing status to use, try the Interactive Tax Assistant Tool for Filing Status from the IRS.
Filing an amended return in TurboTax is easy. This link explains how to amend whether you are using Online or Desktop. You will have to print it out and mail it in.
I recommend you report any state refund as received, if you live in a state with income tax, on this year's return.
