Kelly,
I was there a few years ago and bought a DC827 kit which was a 1/4 impact driver with 2 Li-ion 18v batteries. I can't find that any more but you can find after market DC9182 batteries. Google for that. They are slightly smaller but they plug straight in. I have heard OK things about the 20v to 18v adapters on eBay so you might try that as well. BTW, the DC9182 is 36 Wa, (3600 mAh) so it's a pretty big battery.