Help Quick.

Hello everybody, i'm 18 years old. Well yesterday I was driving my 95 ford escort gt..its a 4 cylinder and what not, 124,000 miles on it. and now the RPM goes way up and it wont go past 40mph without having to tap the gas pedal twice for it to go faster then that, and its very loud. Now has anybody had this problem? My dad said it could be the filter or tranny might need replaced, how much is a tranny? and what do you think it could be? If anybody had this happen to them and could tell me what I should do that would be alot appreciated, by the way i checked my tranny fluid, aint nothing wrong with it.