I took a look at your ad in the classifieds section. Do you have the ad up on any other sites? I'd certainly make sure I keep a current ad on Craigslist. I noticed you're not far from North Platte. I think you'd be in line putting it in the Lincoln and Omaha Craigslist...maybe Denver as well?
Also, a few more and bigger pictures certainly wouldn't hurt. A few shots of the engine, maybe?
The thing you need to remember, though is that it is a very run-of-the-mill coupe. The demand and resale on these cars just isn't as good as the more-desirable convertible and fastback.