The first thing i would try is to make as many bargins as u can. Tell them you will go above the call of duty to do whatever once you get back from IRI, but make sure you keep up your end of the deal. You can try telling them it's a "once" in a lifetime chance, especially this year since you are national champs. You could try telling them by going it could possibly help out in the long term by meeting people in the "industry" (possible jobs?), maybe try to get business cards, etc. to show your parents...
(Are your parents looking?) You could lie and say that if u dont go the whole team suffers...

(dont know how well that would work, maybe you've already tried it)
Hopefully all goes well so all of us over here can see the true RAGE team. Too bad i dont have the money to next day Fed Ex you a ladder so you can get yourself out of the hole you've seemed to dig...