Like some others have said, I'd address the most worn parts first. Start with the brakes. Replace/upgrade as desired or needed (just do the flex hoses unless you Know for a fact that they were recently replaced), get that squared away first. Then the steering. Then the suspension bushings. Give yourself a good foundation to build on. Make the car fun (& safe!) to drive while saving up for the cool stuff.

I wouldn't bother with an add-a-leaf in the rear unless you plan to always have a load in the back. Short add-a-leaves are a huge increase in spring rate, longer ones are less so and I'll bet that the car really doesn't need it. Tune the front suspension ride height to get the stance that you want.