Should I plan on a new car or get it repaired?
This is a tuff nut to crack. If you took it to a good mechanic he should have done numerous tests to try to track the problem down before he jumped on a radiator problem. Was the cooling system tested for hydrocarbons? This would have caused the cooling level to be a bit higher caused by a blown head gasket. I don't know what type of fan clutch you have but was this checked? Have you driven the vehicle thru mud or have you ever hosed the radiator/AC fins to blow out any dirt or debris which causes reduced air flow? Has the possibility of a bad thermostat been ruled out. You can sometimes check the thermostat by feeling the temperature of the top and bottom radiator hoses. Now, the real question is how hot did the engine get? Of course the hotter the worse it will be. The white smoke you mentioned was it smoke or steam.
I know I havn't answered your question but there are so many other questions that need to be answered unless of course you are looking for an excuse to buy a new vehicle. If your not then maybe get some answers to some of the problems that could have led up to the overheating along with what damage if any was done when the engine overheated. HTH and good luck...
BTCS, USN, Retired
2013 Jeep JKU Rubicon 10th Year Anniversary.