Chances at Tepper?

For background, I am an analyst at a consulting firm that works primarily with the DoD, and most of my work is regulatory compliance. I work remotely out of Pittsburgh, and would like to begin elevating my career a bit, so I was wondering what my chances are at getting into Tepper?

For context, I sort of stumbled into this role after a really subpar undergraduate experience (3.1 GPA, Political Science from a virtually unrecognizable university) warranted me zero scholarship money from the few law and graduate schools that did accept me. I found most of my friends going into roles with the FBI or NSA, but I knew I did not want to marry myself with the federal government. I have now found that I really enjoy my role, but clamor for a bit more money, so I began to ponder what an MBA from CMU/Tepper could do for me. There are a few things, however, that stop me from dropping everything in the pursuit of higher education;

1. Would I even be accepted? I am aware that if I bank enough years of solid work, I can hide some of my past errors and flaws when it comes to academia, but will it be enough? Am I irredeemable? 

2. Is an incredibly expensive MBA program that is notably STEM based going to even do anything for my career? Would it be worth the price tag? I understand I can pivot into something else, but I don't really know what the hiring situation is like in IB, corporate finance, and I do know that the defense industry is seeing some of its better days at the moment. 

I accept honest and firm feedback on this, because while I would love to take advantage of the fact that I am walking distance from one of the best business schools in the world, I will not waste my time and effort (and potentially money) for something that is either unobtainable or holds zero value.