i just got that same tank for Christmas today, from my sister! it's a pretty good tank, imo. i have two bettas i keep in one gallons, and they're thriving, not just surviving!
in a one gallon, you do need to do more water changes, but twice a week is pretty good.
there are plenty of 2 and 3 gallon tanks that will fit in smaller spaces, including these two:
i have the 3 gallon, in white. it's a bit awkward to lug around, but if you don't use the undergravel filter, and instead add gravel and siphon, you should do okay. :3