welcome to the forum :)
No reason to panic if you know that Sagales buses take you to Estacio NORD bus station , which is 5 minutes to Arc de Triomf stop of Metro red line 1
and Rodalies.cat railway ,
I clicked at Porta Fira hotel link in your post (what made me understand why you write in L'Hospitalet forum) then I put it to google maps , where you can also see what means of transport are there in the area.
the same at the hotels' website , with the photo (You cannot miss the building once you are in the area !)
Now it depends how mobile you are with your luggage -
and what time you are arriving :::
you cd take Rodalies train to Gornal stop and walk ,
(Metro Hospital de Bellvitge looks to be more than 1km distance)
FGC.cat stop of Europa-Fira is the nearest , but you wd need to change from Metro at Espanya station and get to other area / platform there.
if you are 4 persons , a taxi is also an option , not expensive.
Have a look at Barcelona forum FAQ
tripadvisor.co.uk/Travel-g187497-s301/Barcel… where you´ll find links to transport websites , like www.tmb.Cat
also pls see the Safety sticky tripadvisor.com/ShowTopic-g187497-i44-k27148…
if you have more questions , go ahead
Edited: 15 November 2010, 23:15