I think Barcelona will have to wait until the end of this season to sign new players. It's hard to find good players right now. Each player is currently under contract with different clubs. Nowadays, to think about new players for Barcelona, a lot of money is needed which Barcelona does not have at the moment. As you said, Barcelona have not been able to sign top quality players in recent years due to the club's current financial crisis. But many are not willing to accept these things. These things many people without trying to understand, are blaming Xavi and expressing their displeasure with a coach as skilled as Xavi.
Even though Robert Lewandowski can be said to be a new player at Barcelona, in reality his presence brought victory only at the start, whereas currently conditions cannot bring victory to Barcelona, even though he scored a goal in the 33rd minute, which shows that Robert Lewandowski is still trying hard to score goals even though Barcelona is experiencing quite critical internal problems.
He played in barcelona since last season and how can you said that he was a new player of barcelona? It doesn't even make sense to read it. You score a goal for your club but your club was losing the game and it means nothing. The goal from lewandowski was just a number but it means nothing. Barcelona was losing and this is the fact. Barcelona is performing so poorly and this is the fact. It doesn't even matter how many times people will make excuses for barcelona and lose is lose.
The goal from lewandowski was not changing the result. The club needs to reevaluate themselves regarding the problem that faced by the club. How can barcelona win UCL if it still performs badly like that? Barcelona will be out from UCL too.
It's only matter of time till you will be seeing barcelona will be bottling other competition like la liga and UCL. This club was very weak and this the fact.
Girona was even much stronger than barcelona right now. The problem was on the team and coach. Barcelona needs to sort all it out from the club asap.