Re: I downloaded levitation for mass effect 3 and now I cannot complete side missions.
Curing the genophage completes "Priority: Tuchanka", so you should be able to complete "Heating Unit Stabilizers" and "Book of Plenix". Once the Citadel attack is thwarted you've completed "The Citadel II", but you should be able to take care of "Cerberus Automated Turret Schematics".
Though it's not one of the missions you've listed I've had a similar issue handing of the ciphers for "Citadel: Cerberus Ciphers"; when this happens I follow the following instructions to get the quest back on track:
"Note: You may be unable to interact with Dellk after buying the ciphers from the Spectre terminal. Just head to any other Presidium level, then go back to the Embassies and he will be selectable again. Alternatively, saving and reloading the game should fix it as well. This doesn't always work however (Xbox/PC)."