So, you want to see how I did it? Spoiler: there's not much to it. All you will need is about a yard of fabric, and batting if you need new cushioning.
Let's get going! Remove that nasty old thing and take the string out of the casing. Also, remove your padding if you want to replace that, too. Save all of these pieces. As you have probably guessed, you'll be using these pieces as your patterns. Lay your padding piece out on top of the batting and cut it out. I use the term "padding" loosely, because in my case it was more like foam tissue paper.
Linking up: Tatertots and Jello