Phd with contract searching for a 1 room flat (3 months)

I am a phd student and i work like an engineering in madrid in the Technical University of Madrid. I leave a link to a letter of recommendation from a mine head: https://www.dropbox.com/s/p12a70wrcrjl6rl/recomendation_Oriol.pdf?dl=0

I'm not smoking, I'm a neat, clean and very responsible person. I am 37 years old and over 10 who live alone. I leave a link to my Twitter account and Linkedin for more information about me:
https://twitter.com/oriolupm
https://es.linkedin.com/in/oriolborrasgene

In late September I'm going to do a collaboration of three months with the Humboldt University and need a house from 20 September to 20 December (3 months). I arrived on September 13 but I imagine that is not available before, I pay that proportion to 20.