Lookin for a transmission

Hey guys lookin for a transmission or either some advice on my problem, ok I got a 4cyl T5 in my 90 coupe here recently its been getting harder and harder to get it to go into any gear, other day it finally went south on me and its currently stuck in reverse, im workin on a budget and ive been told it will probably be more trouble and money then its worth to build my T5 to where it will handle the 300+ hp on the motor thats in the car now. Thought about replacing the T5 with a AOD or C4 but then I run into problem of having to get all those transmission lines and crap off of a donor car wouldnt I? Just thoughts on the matter or if anyone can gimme what trouble/money wise what im lookin at to go back to a AOD transmission or possibly a C4. If it would be cheaper to do that anyone know anyone near georgia or surrounding states that has one theyre wanting to get rid of?

nahh it hasnt been powershifted hard least not by me the car did have a set of drag radials and had been run hard by previous owner hence why i done had to replace the rear end and motor in it, the tranny was only thing left in the car from previous owner, speaking of the T5 you said something about a astro T5 what year model should i look for it to come out of and will it bolt straight up or would some modification be necessary. sorry if alot of questions i just never heard of doing swap out of an astro before

thanks guys ill check that out then maybe ill luck up and find one cheap im still gonna tear mine out this weekend and check to see how bad this one is i may luck up and it not be too bad never know