Since i dont know where you located i dont know who can do it for you but heres a link on how convert it
MR2 Technical Knowledgebase - 1985-1986 Mk I Automatic to Manual Transmission...
the tranny you can find through ebay or craigslist near your area or even try a junk yard, i had a good site where you can find them easy but i forgot the site and tried looking right now but got nothing..ill keep trying and pm later