Welcome to Just Answer. I am here to help you resolve your tax and finance concerns. Please feel free to ask anytime you need extra help.
Since you were married and living together at the end of the year, you can only file as married joint or married separate. Head of Household status is not available. Filing status is always determined by end of year marital state.Here is a short statement from the IRS to help you understand this:
IRS TAX TIP 2012-09, January 13, 2012
Determining your filing status is one of the first steps to filing your federal income tax return. There are five filing statuses: Single, Married Filing Jointly, Married Filing Separately, Head of Household and Qualifying Widow(er) with Dependent Child. Your filing status is used to determine your filing requirements, standard deduction, eligibility for certain credits and deductions, and your correct tax.
Some people may qualify for more than one filing status. Here are eight facts about filing status that the IRS wants you to know so you can choose the best option for your situation.
There's much more information about determining your filing status in IRS Publication 501, Exemptions, Standard Deduction, and Filing Information. Publication 501 is available at http://www.irs.gov/ or by calling 800-TAX-FORM(NNN) NNN-NNNN. You can also use the Interactive Tax Assistant on the IRS website to determine your filing status. The ITA tool is a tax law resource on the IRS website that takes you through a series of questions and provides you with responses to tax law questions.