My roommate shut down the network our laptops were using now i cant get on the i

Hello,
Last week my roommate went home for the summer, ( she is travelling europe right now)took her wireless laptop with her and left me with the identical Acer I've used all year long. For five days afterward i still had internet connection up until Sunday morning, that afternoon when i no longer could connect on-line. I do not know the name of our network but the message error stated it had been shut-down. There is no router, PC or modem in our room, just our little laptops. I admit to being clueless about this but can i set up my own network now? How do i go about doing so and what are my other options? Please help I still have papers to turn in.