The Reds boss saw his side beaten 3-2 at Chelsea in the second leg of their UEFA Champions League semi-final on Wednesday, a result which saw the Blues progress by virtue of a 4-3 aggregate scoreline.
With Liverpool now set to end the season empty-handed once again, Benitez accepts that new recruits are vital during the close season.
"Clearly now we have to start thinking about the future," he said.
"We must improve and we will add quality to the squad.
"We have two more games in the Premier League to go and obviously we will try to win them both to give our season a good ending.
"But we will be looking at the squad and preparing for next season. You can see we are closer to the top but we still need three or four new players.
"We need to keep working, our scouting department is certainly doing that. We have two more games and will try to win them and then improve the squad for next season."