If you are saying it is cracked then it needs to be replaced. Check on ebay for the part cost. I usually unscrew the screen and check the model number/ part number on its back, and use this part number in ebay search. once you find the item, buy it and replace it yourself,
Watch youtube to learn. If you do not feel comfortable doing it yourself, seek professioanal help.
ebay link for a new one: http://www.ebay.com/itm/like/190731759334?lpid=82&chn=ps&ul_noapp=true
a youtube of how to replace it: https://www.youtube.com/watch?v=WdZ-iZzW6V8