looking for accommodation in Mouraria, Lisbon

My name is José, I am a 20 year old girl from the Netherlands. I am going to Lisbon for exchange. Currently I am studying Communication and Media at the Erasmus University in Rotterdam.

I am looking for a room for approximately 6 months from mid-august till the end of January in Lisbon. I would love to live in the neighbourhood Mouraria or Santa Maria Maior. 

I am looking for a room that is approximately 15m2 and that costs maximum 400 euro a month. 

I prefer a room for myself that includes a bathroom and kitchen. However, I do not mind sharing the apartment or anything with someone else or multiple people. Although, I still want to have a room for myself, so not a shared one.

The neighbourhood has to be near to the city center and preferably close to the public transport opportunities.