I'd go with turning the heat up - I just had ich on a few fish in my 55... raised the temp to 88 degrees F, the next day I saw fewer spots on the fish... a few days later I saw no spots - I still have the tank set to 88 degrees F because of advice I learned here - I want all to be gone, as well as any parasites that may be floating around. I would also suggest frequent water changes... but according to my family I'm a water change freak... The slightest hint of disease, amonia, or a dead fish and I'm freshening up the water...
good luck, ich is no fun.