How much could I expect to pay for a decent DWI lawyer?

Me and a friend run out of gas. He left walking to get gas. The truck was out of gas and the battery was dead from me playing radio when the police arrived but I was arrest for a DWI. I was drinking but I was not driving the vehicle. The keys were in the ignition and I was reclined in the driver seat. The police report says the truck was running when they arrived and I am having trouble figuring out how I can prove it was not running.