Brightening/Coloring Animated Gifs in ImageReady

I have ImageReady 3.0 and only ImageReady 3.0 (No Photoshop, etc.)

I want to enhance my animated gifs, brighten them, color them. Make them "pop" basically.

ImageReady doesn't have an Adjustment Layer option so far as I can tell, so are there any alternatives or do you have to manipulate each layer individually?

Alternatively, does GIMP or any other freeware/reasonably priced software offer a similar effect?

I've been searching through ImageReady/GIMP tutorials for this but have come up empty-handed so far.

Thanks!