Can I use Gi Bill for a certeficate program?

I am very confused right now. I found a school that i realy want to go to. they offer a cirteficate program in digital filmmaking (CDIA at boston University). It only takes me a couple of semesters to finish it. Gi pays only 680 a month for 36months but the school cost is about 21000. How I my gona get that paid . I am kind of irritated that there is no real information about this online. I hope they take care of this if not I will be mad after serving three full years in baghdad for the sake of getting money for education and ofcouse to defend freedom. Thanx