If just the screen is cracked and the pictures works fine than you have a bad digitizer. The digitizer is responsible for sensing touch and relaying the information to the CPU. The LCD is behind the digitizer and is responsible for displaying the image only.
If touch is not responsive then the digitizer has been damaged and needs replaced. You can usually find the digitizer part by itself but you can also replace the digitizer and LCD as one unit. Digitizers are usually fairly inexpensive compare to the whole unit.
Sometimes its a challenge to find the digitizer only. And this model has the digitizer and LCD bonded so it may be easier to replace as the unit. It will definately be easier to find the part such as the one Anglica has listed. That's your choice on how easy you want the repair to be or how much money you want to spend.