Why not just let it finish its update? If you cut it off halfway through, you might end up with some corrupted files, and then you'll be stuck needing a full reinstall anyway...
Yeah, you should definitely check out the manual to see how it's done, but just a heads-up: updating your graphics card drivers won't touch your computer's BIOS.
To actually update the BIOS, you'll need to manually download the BIOS file along with the update utility and run it yourself—it isn't an automatic process. Even Windows updates don't handle BIOS updates...
Anything is possible, really. I've got a 1TB WD external Hard Drive via USB 3.0, and while large files can hit about 100 MB/s, the average usually sits closer to 60-65 MB/s. My laptop is currently running on a standard 5400 rpm Hard Drive, though things would definitely run smoother if I switched over to an SSD.