I have the same Igo charger you have and it works fine on the Kindle. You can get a splitter and charge two devices at once.
Instead of the Igo Power Xtender
http://www.amazon.com/powerXtender-P...182787&sr=8-10
I prefer the Energizer
http://www.amazon.com/Energizer-Port...3182672&sr=8-2
It hold 4 AA batteries instead of 2 and includes the Igo tip that fits the Iphone and Ipod. The tip alone is $10 on Amazon or Ebay so you can sell the tip if you don't have an Ipod or Iphone and pay about $4 for the Energizer. It works great with my Kindle as well as other devices. It will take any Igo tip.