If i remember correctly, usb 2.0 didn't exist when they rolled out the Jv3 line, so they went with firewire. I doubt you can run it through a converter since there won't be enough power and i think usb2.0 runs data as packets, vs a stream of data through firewire.
your best bet is to install a FireWire card to your computer, although i'm uncertain if you're able to do that with an all-in-one setup. The only other options would be to either get a computer with firewire, or to try and run it through an adaptor like the
DLink Ethernet Parallel Port Printserver and connect to your printer through a network. How to set that up is beyond me, as I'm just relaying some random info from an
old thread on this site.
good luck on your new adventure, the jv3 is an awesome machine. i hope you have rip software and/or you got to see it in operation before your purchase. That machine can have a lot of gremlins under the hood if it sat stale for a long time, or wasn't cared-for that well by its previous-owner, BUT if you get it up n' running.... it is a workhorse.
p.s. i also still have my old one in storage, if you're ever in a pinch for parts or a backup machine that really just needs ink lines and printheads to be functional again. mine are definitely rock-solid dried-ink after unplugging it 6years ago