Can I get my child support order changed?

My ex got fired from his job, we get along good and were still friends but he was only paying 50 dollars a month since he claimed he was still in school ( He was 18 and i was 17 when the order went through). (He wasnt really in school though becouse he got kicked out) and he didnt claim all his income. He was recieving 800 Dollars monthly SSI becouse his real dad had died when he was 3, to lung cancer. He was also living with his parents (so he had no bills)and he was working part time. I too was in school and i was working two jobs in the evnings and weekends.But in the same order once we graduated it when up to 130 a month based on the fact he would be able to work more. l. am married and my husband is in the military he is only an E2 so we dont make a whole lot, and we dont live in the same state as my sons biological father. However my ex is fixing to leave for the coast guard and i was wondering if child sup. would go up? I want to put our 3yr old into pre-k and its 62 a wk