The SPL champions have £12m to spend following the sale of Victor Wanyama to Southampton earlier this month, and Lennon is hoping to use some of that money to bring in new talent.
"Hopefully we've negotiated the tie but we need new bodies in for the next round and we're going to do that," Lennon told reporters.
"We're actively looking at strengthening the squad as there's money available from the Wanyama transfer.
"I'd like someone in before the second leg next week if I can so we can bed them in as quickly as possible. If we could get one in early next week, I'd be delighted but at the moment we aren't close to anything."
The second leg takes place at Celtic Park on Tuesday.