They've told you what skills you need before they can use you. Figure out how to develop them. Take/audit targeted classes, or find some other way to develop and demonstrate them. It doesn't necessarily have to be a full degree program, though if you want to be a researcher in the new field rather than assistant that might be worth considering. If you aren't willing/able to invest in it, maybe you don't need it that much... .
Or find some way to contribute to the new field that leverages your existing skills -- subject matter expert for an application of that technology, for example. We had doctors and data privacy experts advising Watson Health's AI and data reconciliation projects; maybe you can show them some way in which you do fit their needs and can grow that into more general involvement. Or find a different project in the same general area that can use you.
Unfortunately, with a PhD it's unlikely they'd hire you as an intern/lab assistant/code monkey and let you learn that way. Even if you were willing to work for RA wages.