Hello,
I'd love to help you with your project. It shouldn't take more than a day to complete, depending on the complexities of your existing design. I understand what you need in terms of converting pantone colors into black, yellow and grey. I can also output the file into individual color layers to help get your graphic screenprinted. Back in college, I used to screenprint t-shirts by hand so I know what you're looking to get done.
Thanks,
AJ