AFAIK there is no way to adapt USB 3.0 to Firewire, they are totally different protocols. There are Tbolt to FW adaptors but I think they are a bit hit and miss on legacy gear?
The only ray of hope I can offer is if you can find a laptop such as my Lenovo T510 which has a 4 pin FW port. I see the Profire has a separate 12V power input. But even then you might not be out of the woods! I remember the "Great Firewire Chipset FU" of some years ago. Basically if your computer did not have a Texas Instruments 1394 chipset, you were *****d!
I guess you don't want to spend out on a new AI but I think that is inevitable. There are many really good USB interfaces around now at the $200 point. One such is the excellent MOTU M2 . M4 or M6. Naturally more $$$s gets you more facilities. The absolute dog's danglers for quality and especially longevity is RME.
Dave.