welcome to HF heescha.
if you've been getting by w/ the set up you described, you'll be in hog heaven when you get an underquilt.
you'll find lots of info here about the different underquilts available commercially Speers hammock has a the Snugfit underquilt & JRB has several.
also several sources for making your own. ...tim
don`t leave the CREATOR out of the creation!