Loyalty points

Hy there, I’m working on an e-commerce website where I use wordpress for that with wp-ecommerce plugin.

What I need to do is to connect my wordpress website to an already existing website that handles users and points and try to automaticaly extract login access data and points data to wordpress, so users that are on the other website can use the same access data on wordpress too. Also I want to let users to use them points on wordpress to have discounts on some products.

Is there any way to make this thing work? Thanks.