I don't really know if you can buy a spare screen, and you might have a hard time finding one. I would try to search ebay, some chinease stores are offering a whole bunch of spare parts, you might not find the one from LG but you could contact the stores to ask if they could get you a specific one.

There is a problem i a display you need to contact the service center for that you can find the service center address in your pamphlet