Well I once managed Napoli and Cavani/Lavezzi were brilliant. As for young backups, take look at Vaclav Kadlec,Romelu Lukaku or Yaya Sanogo. You may need to sell some players though to be able to afford them.
I bought Lukaku, a bit pricey for £7million (ask the board for extra money) but his doing quite well, only two games but does a good job finding chances. Plus he can only get better
I have already thrown together some bids for lukaku but it looks like he will be out of my price range and Man United already got Kadlec so I may be out of luck.
Edit: Oh and the board aren't being too generous with the extra funds
Go for Kadlec, he's cheap and was a beast for my Napoli team. He was the the best scorer of the Europa League and the Italian Cup. You should definately buy him.
EDIT: Just seen you said he went to Man.Utd. Maybe go for: Lacina Traore, Tomas Necid, Caio, Garra Dembele, Marcelo Moreno (Usually transfer listed).