transmission problem, please help

I have a 1994 Mercury Topaz 4 cyl. About two weeks ago I started noticing that the car would jerk when stopped at a stop light. Then it would hesistate as I accelerated. It also took a longer time to switch to the second gear. I changed the Transmission fluid, but nothing was changed. Is there anything else that I might need to do or are my worst fears correct; the transmission is going and needs to be replaced. the car has 76000 km on it. Any help that could be provided would be greatly appreciated. Thanks

Steve