If its a plasma and just the glass front layer is busted but not the actual visual part then get the glass replaced. But if its a lcd and the panel itself is damaged. Then youd be better of springing for a new unit. But u can pick up a good 42 inch led samsung d5000 non 3d for 500-600 brick
The tech is so so so much better these days 3 years ago i bought samsungs flagship lcd for 1400 off dabs (£2800 in currys lol) and th same size and resolution with led backlight mega high contrast ratio is less than 900