Staring is actually a fairly normal behavior for hamsters. They're not actually staring, simply turning their heads in the direction in which they hear a sound that's causing them to investigate. However, I do agree that 20 gallons is pretty small, especially for a Syrian hamster! Like amity said, there are lots of bins you can get at Walmart, including my favorite, the IRIS bin which is very spacious and fairly cheap. You can get it for $10-$20 or even less if it's on sale. Good luck finding another enclosure
Best wishes