Football shops in Barcelona?

Can you name them and tell me if they sell just FC Barcelona and Espanyol shirts or do they sell other football teams shirts?. My sister is going to Spain for holiday in October and has asked me if i want a FC Barcelona shirt for a present, i don't support Barcelona i support Arsenal, but i have purchased this seasons kits here in England already. I said I don't like Barcelona much, if there is the option between FCB or Espanyol i would choose a Espanyol shirt, but if i picked my favourite Spanish team it would be Atletico Madrid.

So i was wondering if any of you a) live in Barcelona or b) have been to Barcelona and could tell me if Atletico Madrid shirts are available in Barcelona and where they are in Barcelona?

If you want Barcelona merchandise the ideal bet is one of the Barcelona Official shops, there are quite a few in Barcelona. But if, as you say, you prefer a shirt from another team (Atletico de Madrid) then my first try would be one of the huge shopping malls (El Corte Inglés) or a huge sports shop (Decathlon has many in Barcelona).

Other possibilities are one of the many souvenir shops around touristic attractions, they have football shirts from most Spanish teams, and also the shops around Barcelona and Espanyol stadiums on match day.