You don't really need any sewing skills for this DIY project. If you've got a gathered-end hammock, you might be eligible for this easy project -- converting the side stuff sack into a high-performing, two-sided bishop bag.
Not all attached stuff sacks convert well, so your milage may very. I found that some brands have really nice sacks with plenty of room that make for great bishop bags. I have a little more on my blog.