As of now, there is no official announcement from the company's side regarding the launch of Honda CR-V diesel in India. However, it is widely speculated that the diesel version of this model would be launched in India by early 2011.
It may be possible through outside car modifiers. However, since the car has been designed as a 5 seater, adding the rear seats will be tricky. They are unlikely to be comfortable and will leave you with negligible boot space.
You can find the engine no stamped on the engine itself, but if you are unable to locate it, you can also search it on the product information tags on the car, which generally found under the hood near engine bay and on the door frame.