97 Isuzu Trooper Transmission

When i went to change my oil i accidentally drained the transmission fluid instead... i know this is dumb, but im a poor college student who is trying to save money... i've succesfully changed the oil, but i have no idea what to do about the transmission.. i only drained the atf from the pan and havent turned on/moved the car since... what im wondering is: what type of transmission fluid does the trooper take? how do i get it back in (this car's transmission isn't like any other cars ive owned/worked on)? i drained about 3 qyts and the fluid itself was clean... any help would be really really appreciated