AI have a cake due this Sunday. I plan on making a rice cereal treat figure and covering it in modeling chocolate. I know it needs to cure first before working with it. I want to make it in advance but can I store it in the fridge until I'm ready to use it? I need to put it in the fridge because my apartment is set to 90 degrees during the day and I can't change it. I am assuming that 90 degrees is not a good "room temperate" to leave it out!

So is it ok to leave in the fridge or will it sweat? And can I refridgerate the figure once I make it?

It's not ideal to leave modeling chocolate in the fridge but it sounds like you've got to do it! You can avoid the condensation issue (moisture makes modeling chocolate a little wet and sticky) if you keep it well-sealed in plastic wrap until it's ready to use. Then the condensation forms on the plastic wrap instead of on the chocolate's surface. Just to warn you, modeling chocolate is harder to work with when it's cold so you'll want to let it warm up to about 60 degrees F before attempting to use it. 

Here's some info on how to work with rice treats and modeling chocolate: http://www.wickedgoodies.net/2010/08/cake-sculpting-with-rice-treats-and-pvc/