The die hards here actually remove the seats and center console if you have one, and remove their carpets. Some take them to a do-it-yourself carwash and power spray them, others spray with Simple Green, scrub. and hose off. They let the carpets dry in good weather, then replace. If there'* a carpet padding under the carpet, you could pitch it and replace with new padding from a carpet store that you cut to fit.
You might get by without removing the interior if you rent a good extraction carpet steamer with an attachment wand.
Acetone (nail polish remover) might work on nail polish, but be really careful about leather. DEFINITELY test on an inconspicuous piece first. Scrubbing leather with any sort of solvent is a really good way to permanently mar leather by removing the tanning dye. If nobody has any better advice, check with a clothing drycleaners, those guys know how to get just about anything out of anything if it can be done.
Otherwise, maybe look for upholstery at a salvage yard?
97 SE, teflon wiper blades, Dunlop Sport A-2 tires, Leather steering wheel cover, Pioneer DEH-P480MP mp3 CDRW head unit, Pioneer 12-disc changer, iPod hookup, Boston Acoustic 3 way 6x9'*, Boston acoustic separates in door pods, Alpine 4 channel amp in trunk. Magnaflow dual outlet muffler and Ractive stainless tips. Autozone rice pipe and K&N 4750 intake kit. Clear corner lights. Energy Suspension end links.