You will be staying at Hotel Caledonian. Here is the map indicating the walk from the hotel to the University.
You can find all information of going from aiport to Barcelona centrum (an viceversa) using the bus (which is the cheapest, best way of doing so) at:
In fact the bus going from Airport to Barcelona stops at Pl. Universitat (the stop before the final stop at Pl. Catalunya). The hotel is 200 metres from this stop as you can see in the following link.