First thing I would do is replace the muffler with a less restrictive one and address in crimps or crushed pipe areas.Flowmaster makes a nice 2 into 1 y pipe that will outflow the factory one by a ton.Lose the cat or replace it with a high flow one.Maybe have to jet up the carb one size for max performance.
Other than that I would wait until I had the money to do it right.
Rear end swap first and then heads/cam/intake/carb and maybe headers.