At this point I'd go to power steering. If you have the gear box, you're half way there. Go to a salvage yard, craigslist or eBay and get the pump, hoses, resevior and brakets and bolts. Don't forget the BOLTS
I have a 93 that had manual steering. One season of off-road and I said enough is enough. Got on eBay found a guy selling a complete power steering set-up for a 2.5. Box, pump, everything. Probly one of the best investments yet.