Yup, take the card out and put it in the computer. There's no way to speed up the WiFi, it's just not that fast.
RAW files are big. Transfering via WiFi will simply take time, there's no way around it. I use my tablet/phone to preview the jpgs, but RAW files I only tranfer RAW files via USB 3.0. I think it will be some time (several generations) before the in-camera WiFi is fast enough for that - and by then the RAW files will probably have tripled in size.
