I just changed one of those on my friends Jeep on Saturday. Her pulley was completely gone but the belt was still under the hood. Picked up one for cheap at a local junkyard and it is working great again. Car-Part.com--Used Auto Parts Market
has local junkyards with prices and distances from where you live.
Like Jerry said make sure your hose is connected to the brake booster.
Next time get someone that knows how to tow a vehicle.
Did you not have a working horn?