Running a basic stepper motor with Arduino

So I purchased this stepper motor: (data sheet is on that page)

And figured that I could run it off a DC power supply and the Arduino using the Stepper library. I'm able to run the motor but what I'm unable to do is power any more than whatever current is coming out of the digital outs from the arduino.

The stepper motor has 6 pins. I can connect the 4 control pins to the Arduino and it will move as expected, but that leaves 2 pins remaining which I ASSUMED would be for power. However, it doesn't do anything different when I attach a power source.

How can I get more torque and power into my stepper motor?

it's a very bad idea to try to run your stepper motor directly from Arduino pins. You can potentially fry your Arduino board doing it.

From the number of wires you mention i assume your motor i a unipolar stepper, if that is indeed the case then you can use a darlington transistor array AND an external powersupply to run your motor.

You might want to read this:

The data sheet shows only 4 connections (two coils) so the other two you speak of do nothing.

In the link that MikMo posted above, your motor would not have the centre taps (pin 5 & 6) of the first diagram. Otherwise treat it the same.