I don't know what are the taxes outside Brazil, but i'm pretty sure you can get the payments directly from credit cards operators.
But believe me: offering a known payment processor will increase your costumer's reliability over your site. Paypal, Moneybookers, CashU, etc etc... they're way easier to setup compared to or credit card operator's API or some third-party payment processor API (to manage the communication between your site and the CC operator, not to handle the payment like Paypal).
English is not my native language. Sorry for any mistakes and feel free to correct me if needed.