Ok, it's pretty easy. First you'll have to drain the tranny, then unbolt the drive shafts, then the bell housing, then your almost there. Once you have the tranny removed give it to the scrap yard.....pay them to take it if you have to. Imediatly replace with a five speed. All done!
Honestly I don't know of anything that will help a toy auto. They all seam pretty gutless especially behind a four banger. A fresh rebuild might help. If your running bigger than stock tires changing the ring and pinions will help a lot, but still won't feal like the power of a manual.
Good luck