OK, my sons father claims he filed his taxes about 3 weeks ago and he owes back support for my son. The back support is equal to 2 months of his support obligation. I know that federal taxes will be intercepted by the government in this case. How long should it take for the money to be deposited into my child support account.

It could take as long as six months. That's assuming he had a refund coming and did not have to PAY with his tax return.