i need a sling-style laptop sleeve that can fit a 13" laptop and folders

i currently use a peakdesign messenger, but it's way too big for what i carry to school and back. all i carry is a 13" laptop, two (almost empty) folders, and a pencil.

i can find plenty of 13" laptop sleeves, but not many that both have a sling strap and have a big enough separate compartment for folders

should i go for a standard sleeve and put the folders in the main compartment with the laptop itself, or is there a version that fits my needs?

on rare occasions i have to carry a novel or something like that back and forth, so bonus points if something can fit that too