ALASTOR ARRIVES TODAY! -happy dance-
shadica, I've had bad experiences with heaters, and being that I live in Southern California, I mainly avoid them. -shot- The problem is, unless you buy a very expensive heater, which might be very well necessary for where you live, the heaters can malfunction and boil your fish to death. Scary thought. o-o I personally use temperature control in my apartment and 'Sace stays at a good 75-80 degrees, but I understand that's not possible for everyone.
Aquarium salt and, unfortunately, 100% water changes for five days in a row would be your answer; however, I am very rusty in this area so feel free to correct me, anyone.
As for food... I personally use Hikari Betta Bio Gold. My bettas have always gobbled it up like peanut butter chocolate icecream.