21 yo girl looking for a summer accommodation in Berlin

Hi there! I'm Erika, a 21 y.o. girl studying International Relations at University of Essex, UK. I am looking for and accommodation for 3 moths (June, July and August 2015) in Berlin to complete an internship in a local NGO. I'm social and have a diverse range of hobbies: cycling, photography, cooking... But I'm also a reasonably quiet and respectful flat/roommate. I do not mind sharing a room with a female, or sharing a flat with anyone really!:) I am also happy to meet someone who's also looking for an accommodation and cooperate, as larger flats appear to be more reasonably priced. My budget is 300 euros/month. Many thanks!