Hi,
You may be out of luck.
Here is a link to the service manual for your laptop. Hopefully I have got the correct one.
http://www.hp.com/ctg/Manual/c03958968.p...
It shows that the touchscreen is part of the display panel and not a separate item. Scroll to p.17 &19 to view parts and part numbers. It also shows that the touchscreen board (not the 'screen') is not available as a spare part so hopefully it is OK (part #9 on p.17)
If you search online using just the part number of the display you will get results for suppliers of the part.
Below are just some examples, you might find others that suit you better. They are only shown to give you an idea of the cost depending on what type of display you have.
This is for a WVA display.
http://www.ebay.com/itm/LAPTOP-LCD-LED-S...
This is for a UWVA display
http://www.ebay.com/itm/HP-Split-X2-P-N-....
The service manual shows the necessary pre requisites and procedures for replacing the screen.