Help!

Literally just discovered a robin nest in my garden which was in the process of being predated by one of our local felines - one dead chick, but three others still alive, strewn around and possibly injured, and the nest on the floor. I chased the cat away, removed the dead chick from the garden and put the others back in the nest, which I hid in the nearest bush hopefully away from further attention. At least one parent is in attendance, was going mad (obviously) but now calmed down.

Is there anything else I can do? Any hope for the chicks? They look quite well-developed....

Unfortunately I have to go out now for a couple of hours (bad timing!) - but I will check back and do what I can later on.