Yes, upgrade! Get a ten gal with a filter and some tankmates if the betta isn't too rambunctious to put up with them, probably 5-6 small cory cats (special ordering is worth the hassle) and a few otos if the tap water doesn't require tweakage to pull it off. Feed them lots of cukes, zukes, and other veggies because there won't be near enough algae to go around. Or if you love plecos and must have one, get a pitbull (another special order)... just know that they kick out waste like nobody's business and require lots of water changes. None of these "tank cleaners" are low maintenance fish.