Looking for place for 5 months

I am a PhD student from Cuba. I will be going to Tubingen University for 5 month to complete a PhD research stay. I am studying Psychology, with a focus on Neuroscience. I am a very quite and clean person. I am not interested in partying. I am just trying to find a place where I can focus on my research and make the most out of my time at Tubingen, since my number one priority is my career. That is the main reason why I would prefer a place for myself, instead of a share space. Since I am on limited budget, I cannot afford to spend more than 700 per month on rent and utilities. This will be my first time visiting Germany. Hence, I would prefer a place near the University, or at least from where it would be easy to get to the University. Text me if you need more information.