pyarrau

I have been having overheating issues ever since I bought this car and these are the things I have done already:

I have skimmed the head (5 tow) and replaced head gasket with original.
Timing has been checked and torque on head bolt ok.

Radiator has been rodded out (was clogged), clamps on water hoses have been changed.

Water pump was checked but was good, (not replaced).

After everything NOW the car ran fine in town but the A/C wasn't cooling properly. when I took it on long journey to the country it started to overheat again...

NOW I am hearing that I need to change the radiator to a double core as I only have the single core. ( The radiator specialist, convinced me by saying that these small single core radiators that come in the card, were made for use in japan in their cold climate but cant put up to the hot climate we have in Jamaica). Radiator replacement is said to be about $15,000JMD

Any help and suggestions are welcomed.

I NEED HELP.....this overheating problem has been haunting me for almost a year now.