If it were mine, I think I'd drain that cleaner crap out, fill 'er back up with 50/50 (works well in the Midwest), and see what happens. You'll have to drain the radiator anyway if you were to replace it. If it is bad you could drain and save the fluid to put in your new radiator.
I don't know how much it would cost to repair the radiator. When the radiator on my (non-Yota) rig started to go, I swapped it out for an all metal 3 row radiator. The stock radiator was leaking where the plastic (!!!) met the metal. I ordered mine from RadiatorBarn.com and only have good things to say about them - cheap, fast shipment, good product, free T-shirt.
HTH