Just thinking out loud... after half the season is done, there are three main purchases as far as I can see which could really improve the team; Dzeko, Shaqiri and Jose Enrique. I think these purchases are relatively realistic for Juventus.
Dzeko
Vucinic ----------------------- Shaqiri
Claudio -------- Vidal
Pirlo
Enrique ----- Chiellini ----- Barzaghli ----- Lichsteiner
Superman
Subs: Matri, Pepe, Estigarribia, Elia, Pazienza, Marrone, Appelt, De Ceglie, Bonucci, Sorensen, Motta, Storari.
IN: Dzeko (35m), Shaqiri (15-20m), Enriqe (10-15m) = 60-70m.
OUT: ADP (free), Quag (8m), Amauri (1m), Toni (1m), Iaquinta (2m), Giaccherini (2m), Krasic (10m), Grosso (free) = 24m.
That's a total of 36-46m spent plus some hefty salaries off the books. The club will have to pay Dzeko the same salary (€6.5-7.5m) to tempt him away from City but there is the added attraction of being a starter at Juventus. This team seems, to me, capable of reaching the semi-finals of the Champions League based on the strength of the defense and midfield.
Even if Dzeko is not possible, I think Shaqiri and Enrique will improve the team enough to easily progress past the group stages of the Champions League.