I got married in 2007 and?

now it is time to file taxes, however, my husband owes back child support. If we file jointly will they take our refund and put it toward that? We have a child together and I was going to file married filing separate but then I am not elidgable for EIC and cannot claim the daycare money spent. We were separated for about three weeks recently but have reconciled....does that mean that I can claim Head of Household?