Help, iTunes 11 app sync problem.

Recently upgraded my sisters brand new MacBook Air (11" with 64gb SSD) with iTunes 11.

She also has a 64GB iphone and a 32gb iPad for her kids. now when she goes to sync the iDevices iTunes asks to copy over purchased items such as apps and music, if you click no it warns that all purchased items not synced will be deleted from the iDevices. This is a problem because as it is she is already low on drive space on her Air and like 40GB worth of apps on the iDevices.

This seems like a stupid restriction, or is there something I'm missing here? There seems no way for her to sync her devices without freeing up a huge amount of space of her Air (her iPhoto library is 40GB alone) which would make the Air pointless.

Any help would be greatly appreciated.