Hello Daniel, you can take the radiator out and take it to a radiator shop, most of them used to be able to replace the tank and/or seal. Unfortunately it usually costs more than a replacement radiator. The web site you found looks to be a good place to purchase radiators, they claim that it meets or beats OEM pars. For the price it would be worth trying, although it will still have plastic tanks, I believe.
The administrator has disabled public write access.