What are the necessary qualifications and salary?

Not sure about a temp agency (though I can tell you, you'll pay more going that way with still no guarantee it will work out). May I ask what you've tried so far in terms of where you've listed it, the requirements/qualifications, and what kind of wages and benefits you are offering? There may be other advice people could offer with a full picture.

Location? Job description? Rate of pay?

What are you willing to pay? What is the job description? Are there benefits? What is the location? What are the requirements for experience? Kinda need to know all these things.

Edit to add: unless you are willing to pay a living wage, offer benefits, then you will have a very hard time finding someone who will apply/stick around.

Before going to a staffing service, I'd maybe consider increasing the posted salary by 50-100% and really making sure the description and requirements is clear.

Odds are, you'll get more quality and not-quality candidates that you can filter out.

You'll already be paying that extra money for any staffing agency (probably with a substantial buyout if you want to permanently hire) so you may as well use that part of the budget to make the job more attractive.

DM me the listing, I know someone who is looking for a job in that area and will pass it on to them.