Yep, I would get a new motor. Your tractor turns 540 rpm at the pto. That pump will want to see 3600 or so.
So you would have to get creative with gearboxes and.or pullies to get the speed up. And to just totally replace the pump with a PTO pump designed to run on the 540 would likely cost more than a new motor, cause PTO pumps are pricey.