Jol watched his side draw a blank at Werder Bremen as Nils Petersen's 55th-minute goal gave the German side victory on Sunday.
Maarten Stekelenburg kept the scoreline down with a series of saves, and the manager afterwards conceded Fulham desperately need to add more quality to their attacking game.
He told the club website: "We need pace and a little bit of quality. Berbatov was good, but he can't do everything and we needed to get in behind.
"We will try to get someone up front. We need a few more goals. Since Clint Dempsey left we do not have enough goals in us, so we are working every day to get someone in.
"We have some high-quality players in consideration and we would like another midfielder as well."
The need for reinforcements has become more urgent still given Alex Kacaniklic suffered a hamstring injury in Bremen.
Jol said: "He may be out for a couple of weeks. That is not what you want from pre-season."
There was some cheer for Jol in the promising performance of Mesca Na Bangna, who was twice close after coming on as a substitute.
"Mesca came on and looked good," he said. "He was probably our best player on the day even though he has only played with us twice. That was positive."