Grab Some Information From Site using API

Hi
I want to grab some information from a site using API...suppose i want to grab information of Reward Points (PayBack Points,Shop Clue Points)...How can i grab this information from payback.in to my site using API. is there any one who can help me out with API.

ali.mdmkn@gmail.com...its my gtalk id...if possible you can contact me on chat also, i Shall be very thankful to you for this.