1996 Daewoo Lanos overheating

Hi my car is actually a ciallo my car is fine to drive around town but on very hot days it over heats after about 45 min of freeway driving, the water bottle remains full but is boiling and my temp gauge doesn't go to hot, yesterday this happened and for the 2nd time l found heaps of hair like stuff in my exhaust, l was told this could be the insulation from the cadalic converter?Is this true and what does the converter do. The hair is very very long quite soft and whitish and brown in color but it seems to be never ending when pulling it out. When the car overheats it just stalls and l have to wait for it to cool before l can start it. There is no water in my oil. Any suggestions l am a female and we get ripped off by mechanics lol l also had the head done 6mths ago a new radiator and water pump