Child Support Between Delaware And Texas

Child support case open in 2004 her in state of Delaware after mother ran to Texas with two children and hidden in shelter, at the case judge awarded arrears and in June 2005 I moved to Texas after not able to afford visitation, had children for weekends in 2009 married and had another child by same mother. I need to know 1) how to get child support o stop withholding from my pay check now that I married mother? 2) to get all three of the children same name, son last change in Delaware filed different in Texas ,daughter has two last name , baby has my last name? help!!!!