Ok so I need an op amp that I could hook up to the same power supply as the Arduino board, get the 0-5 out of the board and amp it up to 0-10.
In case you don't know this, you'll need a slightly more than 10V powering the op-amp. Then, you just need an op-amp circuit with a gain of 2 (an op-amp and two resistors).
The Arduino doesn't have a true DAC. It has PWM which can be filtered (with a resistor & capacitor) to get a variable DC voltage.