the tranny filter in a honda auto tranny is not changeable without dropping the tranny and opening it up. i hope a shop didn't charge you for a filter.

anyways, i think your tranny is on the way out. you have a few options, given the age of your car i would either get used auto tranny installed or swap to 5sp. you may even want to sell the car for another. whatever you do, don't spend money on rebuilding or buying a new rebuilt tranny cause it'll cost more than what the car is worth.