Many fonts on Typekit support Portuguese. You can browse fonts that support Portuguese by selecting "Portuguese" from the list of supported languages in the sidebar under browse fonts.
Portuguese is included in the default option, so the Portuguese characters will be available to your website within a few minutes of publishing your kit.
You may also create a custom language subset which includes Portuguese, to reduce the size of your kit. The Language Support & Subsetting help page has more information on the character set options.
All fonts that support Portuguese include the following letter characters, at minimum: