Hiring it out would be expensive, if you could find anyone to take the job, because you would likely have to have engineered plans approved by your building department. DIY might not be as bad as it sounds, if you have a few jacks.
If it is built with a trussed roof, the trusses won't be strong enough to raise the walls by lifting on the bottom chord unless all of the trusses have hurricane strap installed. When jacking, use a 12'+ 4x4 to spread the load across as many chords/joists as possible. Same when placing it on temporary posts.
There are 2 basic approaches. Building a 2x4 (2x6?) knee wall under the existing wall or build a poured concrete or brick/block wall underneath. Both ahve some issues.
With the wood knee wall, you really should replace the outside sheathing so that it spans the seam. Or, possibly, skip the seam. Cut the nails that hold the studs to the bottom plate before lifting. Once in the air, put a 2' 2by under each stud and "sister" on a 4'-6' long 2by, with construction adhesive and nails.
With concrete and/or brick/block the problem is installing hold down bolts that run from the original floor though the new knee wall into the bottom plate.