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The source image is only 500px × 336px. You need a high-quality upscaler to get it anywhere near sharp since you are increasing it by 250%. Try Perfect Resize 7 (formerly Genuine Fractals).
 
No.

The image is 500*336 pixels in size, if you scale up to 1280*800, each pixel in the original image is now consuming >4 pixels. No amount of interpolation will make it look decent.
 
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