git clone git@github.com:YOUR-USERNAME/YOUR-FORKED-REPO.git
cd into/cloned/fork-repo
git remote add upstream git://github.com/ORIGINAL-DEV-USERNAME/REPO-YOU-FORKED-FROM.git
git fetch upstream
This was useful for me when we created a new branch for a new major release, but were still working on our current version as well. I cloned our repo again and kept the new project on our new branch, but also wanted to get my stashes there.
git stash show -p > patch
You'll have to specify your stash and name your file whatevery you want. Do this for as all your stashes, and you'll have patch files in your pwd.