Hi Calvin :-)
Alberguinn is not very close to the center of Barcelona. You can walk to the Ramblas in approx 30 minutes, but it is much faster to take the train (1 stop) or Metro (4 stops) or even a Bus. Alberguinn is in a zone of Barcelona called "Sants" and is VERY close to the main train station and well communicated in that sense. Easy to get here from the airport, from other train station os from other bus stations. The nightlife of Sants is not great, but you can go to the city center and there is always a night bus that will bring you back. On Saturdays, the Metro goes all night.