a turbo buick familair shop that knows what they are doing should be able to complete in under 2 hrs provided there's no other hangups discovered to deal with like twisted yoke splines , cracked flywheel, bad u-joints, broken trans mount , damaged cooler lines
around here you can figure $250-300 plus fluids and misc.
might as well replace the trans mount unless its brand new since you can get one for around $11-17 and have it handy for the mechanic since they have to remove for swap anyway
if your doing a converter be sure to have the correct torque converter bolts for it if since some use through bolts and stock doesnt
if you havent done already plan on doing an external trans cooler , but thats something the average car guy can handle on their own, if you dont feel comfortable doing it have the trans shop do it
hopefully they are familair with the buick turbo 2004r and dont damage your tv or shifter cable doing the swap or it will add up on the parts needed for this swap and also the time they will have it while they call around looking for those parts