Heya NtK!
I'd recommend the purchase of a powered USB hub to power your passthru. Just make sure that the hub can push 5V at 500-1000mA on each port. That should free you of being within arm's reach of your computer while still giving you the power that your computer is likely putting out*. I gave up trying to find the thread here on ECF for the preferred hub; something like
USB 2.0 4-port Hub, Bus-powered, Super Slim should suffice, if it comes with the external power supply.
I personally use one of Apple's post-recall wall chargers to power my passthrus-- if I hadn't received it with my phone, I likely wouldn't have purchased it freely ($30.)
Amazon.com: Apple USB Power Adapter for iPod/iPhone: Electronics The biggest advantage is that it's super compact and travels very well.
Now, don't you just love your e-Hookah?
-HB
*To check on your computer's USB bus amperage, open Device Manager>Universal Serial Bus controllers>Generic USB Hub (you may have several) and click on the "Power" tab. Most computers will cap at 500mA.