My method of doing it isn't the best way, but it worked and was quick.
Basically I moved the image down (to remove some of the black, leaving a gap at the top of the picture), copied part of the sky from the top of the image and rotated it 180' and moved it into the blank space at the top to fill it.
Next I used the spot healing brush tool to paint over where the new sky part was, to merge it in with the gradient of the old sky.
Removing the barn can be done in a similar way.
If you leave me your email I'll send you a quick (it takes about 30 seconds) video of how to do it.