If you have an additional usb port to spare, you can try using a two pronged usb cable to supply additional power. Something like this:
Amazon.com: Cables to Go 28108 USB 2.0 B Male to 2 USB A Male Y-Cable (Black): Electronics
edit: Oops, just realized you already bought a usb hub to solve the problem. Guess it's good to keep the Y cable in mind in case you ever need it