What about Javier Saviola? People have mentioned this guy before, he will be a lot cheaper than any of the other candidates for the striker-role. And then we can have enough money to buy Diarra, Buffon, Gallas and Oddo.
Actually I think Saviola could be a good partner for Gilardino, and replacement for Inzaghi. I think they have complementary skills, and he has great speed and an eye for goal.
Introducing Saviola:
http://www.youtube.com/watch?v=McEqY41WwZk