You can't. Well..not for the front and back. You can get Suspension Techniques springs from JCWhitney to drop the front. They are listed as a Lumina spring. BUT, there are no coil-over springs to drop the rear, because there are NO springs in the rear of your car. For the rear, the options are limited to these:
1. Aftermarket coil-overs. Very pricey.
www.fastfwdperformance.com
2. Replace your rear mono-leaf spring with one from
www.flex-a-form.com This will give you a 1" drop in the rear, but it is not an easy install.
3. Add weight...lots of it to the rear. Sandbags work good.