Hi,
You need to replace the digitiser on your phone.
Here is a link on how to dis-assemble and re-assemble your phone. ''Do not remove parts that you do not have to to gain access to the digitizer''. The start of the actual digitiser removal is shown approximately 7:30 minutes into the video.
https://www.youtube.com/watch?v=WvrtIvARE8M
Here is a link where you can get a digitizer. You will have to choose the one you want. This is only one option, you may wish to try another source. Just "google" digitizer for samsung galaxy s duos S7562.
http://www.etradesupply.com/catalogsearch/result/?warehouse=0&q=galaxy+s+duos+s7562