Hi there,
so you can't find your apt.conf? It must be there!
apt.conf.d is, like the name says a directory! try to change to the diretory and you must get something like this:
***@linux:/etc/apt/apt.conf.d> ll
-rw-r--r-- 1 root root 390 2004-05-15 21:51 apt.conf
-rw-r--r-- 1 root root 164 2004-05-29 17:26 gpg-checker.conf
-rw-r--r-- 1 root root 102 2004-05-16 21:59 list-extras.conf
-rw-r--r-- 1 root root 48 2004-05-16 21:59 list-nodeps.conf
-rw-r--r-- 1 root root 206 2004-05-16 21:59 pkglog.conf
-rw-r--r-- 1 root root 101 2004-05-16 21:59 post.conf
***@linux:/etc/apt/apt.conf.d>
contents of this dir. is on debian as it is on suse the same!
let me know if I helped you!