tranny replace or fix?

my 65 with 302 3pd auto has another problem...the tranny leaks. i can drive it around for a bit then park it and it gushes out lots of tranny fluid for like a min then stops, and then sometimes i can drive it around and park it and maybe one or two drops comes out(i keep tranny full all the time because it leeks) i took it to a tranny shop and they want just under 600 bucks to service it and replace exterior seals to keep it from leaking. i eventualy planned to replace it with a tremec 5 spd or AOD later down the line. my question is...should i have my tranny fixed or save up the extra money and buy a 5 spd or AOD? the purpose for the car is to go fast, both road racing and street racing, as well as a daily driver. im not to familiar with what power and performance can come out of a 3spd auto. so what does everybody suggest me to do? im 20 and on a budget. thanks

any suggestions on how i could keep my tranny from leaking for now? we were thinking maybe putting some high temp silicon around it?

k..if i were to do it myself. how would i go about it? ive taken the same setup out of a 65 falcon before but i just riped it all out through the engine compartment because it was all going to be replaced. i dont think i didnt it correctly. anybody know of a site or anything that shows how to do it? or just the general idea? im sure i could figure it out but better safe than sorry. also, where would i find a complete seal kit for this?

i have a tranny cooler on my stang. its new(so it looks) its bolted into the front frame that the radiator sits on which just so happens to be behind the fron air dam where it looks like it wouldnt get good airflow...could this cause some of my problems?