Obviously, any coach including Xavi wants to have many players in their team and they want to hire the better layer they have right now. But I think that's not something they can do that for the Barcelona team, because Barcelona is not in a good financial situation, and hiring new players can't be easy for this team with the current situation they have.
Financial situation is the main problem Barcelona is facing which is the reason they are unable to buy players, but Xavi should have managed the little one he have to be gaining good results for the team. Playing against Vallecano is not a good one especially seeing that Barcelona have been winning them for long, and they need some points to fight for title with Madrid. I think Xavi need to work on his tactics as a coach to giver Barcelona a better performance.