I have been going through divorce. It is not finalized. When I filed taxes this year I got stuck with our first time homebuyers pay back plus a past due from his failure to file our 2011 state taxes. It nearly took half of my refund. He has not yet paid child support and I am trying to get back on my feet. What can I do about this. I do not feel I should have to pay the full amount if any for that matter.

As you said here, it was your spouse who owed that money, you might be able to claim injured spouse relief; you need to know about getting that injured spouse relief:
To be considered an injured spouse, you must have made and reported tax payments, such as federal income tax withheld from wages or estimated tax payments, or claimed a refundable tax credit, such as the earned income credit or additional child tax credit on the joint return, and not be legally obligated to pay the past-due amount.
( If you live in a community property state, special rules apply. For more information,, see IRS Publication 555, Community Property.); If you filed a joint return and you’re not responsible for the debt, but you are entitled to a portion of the refund you may request your portion of the refund by filing Form 8379; You may file form 8379 along with your original tax return or your may file it by itself after you are notified of an offset; You can file the Form 8379 electronically. If you file a paper tax return you can include Form 8379 with your return, write “INJURED SPOUSE” at the top left corner of the Form 1040, 1040A, or 1040EZ. IRS will process your allocation request before an offset occurs ; If you are filing Form 8379 by itself, it must show both spouses’ SSN# in the same order as they appeared on your income tax return. You, as the injured spouse, must sign the form; I guess you may contact the IRS for more info in detail.