For a start if you don't have a compositing app then you are probably a bit screwed. Why don't you download a trial of after effects or shake and have a go (even photoshop in batch mode might do it).
ok the only thing that raytracing will be giving you is the relfections right? so I would render it with raytraciung turned off. For the floor for example what you can do is turn off primary visiblity on all the objects apart from the floor. Now you will get the floor rendered but nothing else. However you will see the reflected objects in the floor. It basically makes the geo invisible to the primary ray but visible to all other rays.
Are some of your objects static? That way you could render them once and then render anything that moves as a 2nd layer and comp it in. Do you see a re-curring theme? Doing all this stuff in 2d will save you loads of time and effort.
Technical Director - Framestore
Currently working on: Your Highness