Was in Barcelona last summer, what a city. The day we went to the Nou Camp tickets were on sale for all upcoming matches, so you should get them easily enough.
We stayed in the Marina hotel and I could not recommend it highly enough. Nice pool on the roof, amazing buffet breakfast, in a nice area can walk down to the beach and along the sea front into town. Also we walked from the Ramblas every evening. The hotel also has a wonderful spa in it.
[broken link removed]