Dynamic attributes depending on the a $_GET variable

hi all,

the products I am offering depends on a custom search I built into wordpress.
So when someone select a product, I need to store with it a specific ID that is related to the search that the visitor did.

How can I get this information into the woocommerce cart?
The information is avalible in the $_GET variable when the products are listed, so it is easy to retrieve. My questions are:
1. what is the best way to add this information to a product
2. how can I further store this information in the cart and payment.

thanks