I'm no native speaker and I don't do language exchange but I'd like to offer you a correction and some tips for finding language partners.

The sentence in your title should be: I need to learn English.

Go to the notebook section and correct Portuguese entries by other users or go to the answer section and answer questions about Portuguese. Write notebook entries in English and actively take part in the English discussions. This way you can practice English and also meet people who are studying Portuguese and might be interested in a language exchange. Good luck!