Juicebeats

I have some Polaroid photos I took with a Mamiya 645 medium format camera, but the actual image that shows up on the polaroid paper is 1.5x2in. I've attached a scan of one. My questions is how can I scan such a small image to get better quality so I have a digital copy? I've tried several different sizes on the scanner and set the ppi to 1200 for highest quality scan. I can't seem to get a crisp image. The scanner I'm using is from an HP Officejet Pro 8710.