Changing "Product [product:title] added to your cart." message in Drupal Commerce
There are several Options,


got to rules and disable the add to cart rule, then create your own.
Use this module https://drupal.org/project/stringoverrides to override the string. The string to override is this "%title added to your cart."


I wouldn't edit the module file commerce_cart.rules.inc -> function commerce_cart_rules_add_to_cart_message($product) as when you update it will just overwrite what you have done