If you bought it new, you should have an AC adapter for it that plugs into the DC port on the shorter cable with the LED on the cable you do have... I assume you got it used since you don't seem to have the AC adapter.
That all being said... There's a cradle accessory for it that can provide line-in and line-out as well as AC charging and USB (though the AC charging requires the AC adapter you should have gotten with the H10). You would probably be able to get some sort of car charger for it, though it will need to have the right adapter tip (polarity is center-positive, the tip is about 3 mm in diameter with a 1mm center) and be able to lower the voltage from 12 to 5. I would recommend finding one with changeable tips (to make sure you get the right size tip and can ensure its center-positive) and an adjustable voltage dial (so you can make sure it outputs only 5 volts). Added benefit would be you could use it for other things as well, like cell-phones or laptops.