It is believed that the Catalan club's initial bid of £35m was rejected but Arsenal have named a price for the 24-year-old and both teams have until August 31 to reach an agreement.
"There is a sum of money set aside for the signing," said Guardiola. "But if it doesn't work out it will be kept for something else.
"We will fight to the end to get Cesc because we believe he will improve the team and the squad."
Barcelona have publicly courted the Spanish international for the past four years, with Arsenal repeatedly stating their wish not to sell the player.