Thanks for the responses, everybody. I'm reluctant to pursue another masters degree as I just finished my master's in HCI (and manged to get out of that debt free). I have considered taking some CS classes as a non-degree seeking student in order to develop a relationship with some more professors and better my understanding of concepts that I may not currently have a good grasp on. I don't know anything about the financial offers from OR. I know that I won't take the offer if I don't have funding of some sort.
I guess I feel like I understand the application process better now and feel like I could put together a better application, but I can't gauge how much better it will be. I look back on my application and feel like I could have better articulated my research interests and I feel like I better understand the need to show more abilities in that specific area rather than just showing that I have a master's degree and I've done research. I guess it's not so much reluctance about the school, but a nagging "what-if" feeling about what I could do if I tried again with the knowledge I have now.
But, I still haven't heard back from the school, so this is still all speculation.