Kubota KX121-2 Hydraulic pump

Anybody out there know where to get a cost effective replacement pump for a KX121-2. My machine is is only getting to 1500 psi on the right track drive, boom and bucket. I swapped the pump pressure lines and the low pressure problem followed to the left drive, arm etc. I was looking at the parts catalog and pricing the valve plate, pistons, cylinder block, seal kit and the price is getting close to a plug and play unit from Kubota.

Thanks