Where can I find a power cable?!

So I’ve got this old external hard drive lying around, probably 3 or 4 years old now.
The thing is, I managed to lose the power cable somewhere along the way, and lately, I haven't been able to track one down anywhere here in Washington, D.C.—tried looking at Chipotle, Boston, even H&M... nothing.
I don't actually know the technical name for the power connector, but if I had to describe it... it's basically that kind of port where a mouse or a keyboard would plug in perfectly, you know? Like, a round input, a little notch at the "12 o'clock" position, and then 6 pins inside—two on the bottom, one on the left, and one on the right.
I'm just trying to figure out what this cable is officially called, without having to give this whole weirdly descriptive explanation... or better yet, does anyone know where I can actually pick one up around town in the US?
Thanks a ton 🙂

http://www.grzelka.de/datenblaetter/...%20GP-2000.pdf

- page 4, those N- and NS markings

or maybe something like this: http://www.eta-usa.com/powercord.html

So, where am I supposed to find that?

At least you've got photos and some labels you can show someone... if they don't know what's up at Chipotle, try checking here—they usually carry everything: http://www.microcenter.com/

One thing though: is it just a cable? Or does it include the transformer? If there's a transformer (that heavy brick) on the cord, you could technically use any external power supply as long as the voltage matches (but check that carefully!!!!!), and you could probably get a technician to solder on a new connector...

Then again, with how much hard drives cost these days, I'm not sure if it's even worth the hassle...

Alright, here’s the answer to that same question from the Google forums:
"That isn't a PlayStation 2 port, it's actually a 6-pin mini DIN. You won't find a direct USB adapter for it. Try searching under mini DIN, though even that might be a pain because some manufacturers use totally different pinouts."

So I don't need a power transformer, just a cable... I honestly thought this would be way easier to track down. Might just end up looking for an external enclosure instead...
Thanks for the help!