tranny problems

ok guys, i just had the pressure plate replaced in my 94 accord little less than a month ago and ever since i had it done, the tranny has been makin a wierd whining noise and last week it just stalled on me and when i started it back up it wouldn't go anywhere. I figure that it's either low or out of tranny fluid, but the question is, did it do any real damage?? Can i just fill it back up with tranny fluid and take it back to the place and have them check for leaks? if so, is it possible to fill the tranny at home without having it towed somewhere?

thanks