Bruce told the club's official website: "He has been a great signing for us. We nicked him out of Arsenal and he got nine goals last year to help get us up.
"And again he is one of those who wants to prove that he can play in the Premier League, at the highest level.
"We have been delighted with his contribution, he has done fantastically well.
"There must be some good players in Sweden to keep him out of the national side. He never gets a look in."