Looking for Short-term Rent

I will be conducting research for my thesis in Berlin this summer and need a small flat to stay in for about a month! I am studying Holocaust and Genocide Studies. I am very friendly and outgoing so I would love to make some new friends. I am a non-smoker and generally keep pretty quiet. I would like my own flat but am open to renting a room in a flat. I would like access to a washer and will need wireless internet. I have lived in Germany before so I am familiar with the culture and customs of Berlin. My German is okay so please feel free to help me improve.