To help anyone else looking for accommodation in Barcelona. If you have the money then it may be well worth staying in W Hotel Barcelona
When my parents visited me in Barcelona they stayed in Vinci Mar hotel. They said that the hotel itself is brilliant, but the area wasn't the best because it's not so central. There's a rooftop pool, which was a must for them. The best area to stay in is probably Eixample.
Then there are apartments in Barcelona. I won't place a link because that's probably against the rules here and I don't want to get banned. But you can find them by following the link in my signature and going to the Barcelona site.
I hope that helps!