My choice would be Alba left defence, Chiek Tiote defensive midfield, Nicolas Gaitan and Shingwa Kagawa (would prefer Muniain to Kagawa, but it appears we are going for Kagawa and he is available) attacking midfield and Clint Dempsey striker, with Powell and Cline for the future. I don't see that collection breaking the bank but they would vastly improve the squad. Will Keane to come up.
Out would go Owen, Berbatov, Macheda, Anderson, Pogba (does he really want to be at United?) and Giggs to retire.