Are you a member of Ravelry.com? It's free to sign up if you're not already. There are several members who have KnitPicks Shine Worsted in "Terra Cotta" in their stashes (click here
to see the members who have this yarn stashed) ... you could see if someone would be willing to sell you a few skeins to finish your project. It looks like no one has this particular color listed as being for sale/trade, but members are often willing to help when it comes to discontinued yarn (especially if they don't have a project in mind for the yarn you're looking for), so it wouldn't hurt to try before you end up frogging!