You may be able to use continuous rasterization to retain quality and scale when nesting your current comp into a parent comp, but the specifics will really depend on the actual content.
It sounds like you want to deliver a higher resolution product. There are two options. One is to place your original composition in a larger one, turn Collapse transformations, then scale it up to the desired size. If your original composition has Continuously Rasterize turned on for all vector layers this will work for all vector layers unless certain effects have been added to the layers. There is another way. I would suggest that you use the Scale Comp script. You can find it by going to File>Scripts and select either Demo Palette or Scale Composition.
Once you have got it open just set a new comp width and all of your work will be scaled up and the animations will work just fine. You then may have to go through the layers and turn on continuous rasterization for all AI layers.
Great! Thank you!
Thank you Rick, this work perfectly well for me!