First off, why did you decide to shoot at ISO 800? You obviously had a tripod or some kind of support since you shot at 1/15 so why not just crank it up to 1 second at ISO 100?
Second, that exposure would have been too long for this scene. It's overexposed obviously. You have no black in the photo.
Third, why shoot it at 5pm? You could have saved yourself $50 (or more) on the filter and just waited another hour until sunset. Wait another thirty minutes and you'll hit twilight and get a poster quality image.
My suggestion, figure out when exactly twilight is for your area and your day. Go back and set your camera to ISO 100 F8 30 seconds on a tripod. Take one picture at the exact minute of twilight (civil twilight). Come back here and post the picture. I guarantee you $20 paypal it will look awesome.