30y German student looking for a room

I am Dennis, a 30 years old German student. I am studying Human Resource Management in Master in University of Southern DENMARK. Because I am very interested in meeting international people and other cultures, I thought it's nice to make one more semester abroad and go to Portugal. I make my semester at ISCTE-IUL - and I am looing for a room from beginning of September until end of December. I know the semester is one more month, but because the exam period is over some weeks earlier, I am going to save some money and go back home little earlier. 

Since all the student accomodations are already full, too expensive or they don't respond, I need something very urgent! Furthermore it would be really nice, when they way from my accomodation to university is not too far...