Actually we don´t register regional domains out of Argentina. Although you can register your domain in the NIC of your country.

Here you can find a list of differents NIC´s. If your country is no listed, find it here: http://www.iana.org/root-whois/index.html

Bolivia	Brazil
Chile	Colombia
Costa Rica	Cuba
Ecuador	El Salvador
España	Guatemala
Honduras	Nicaragua
Panamá	Paraguay
República Dominicana	Uruguay
Venezuela