I am looking to buy a laser distance meter and to connect it to a motor and a 3g cellular to control both the motor and to mesure the distance. I will appriciate your advice on how to do so. thanks
It sounds like all you need is a single beam distance measurement. There are lots of devices like the Bosch laser distance meter. But i don't think they have the range you want, and also probably no computer interface.
SICK makes a 2D laser scanner that used to be standard in robotics. (You can see many of these mounted atop the DARPA Grand Challenge cars for example). I think the standard used to be the LMS200 series, but it looks that has been replaced by the LMS500 series. These work outdoors, have ranges up to 80 meters, and are easily interfaced with a computer.