Engine Cooling problem
2000 Other Hyundai Models Four Wheel Drive Manual

recently my lower radiator hose burst/cracked and i as result my car overheated. I am not sure how long i drove itfor. I have changed the hose but was unable to find the exact same one so installed one very similiar with a samll hose restriction in a turn. I have been operating the vehicle, the engine runs normal, climbs steep hills well and has normal power. However my coolant pressure is higher than normal and I am loosing coolant from it boiling out the overflow resorvior. I dont want to consider a blown head gasket and am wondering can a old radiator cap cause this. A friend who is a mechanic removed the thermostat previously due to another problem. Do I need to install a new thermostat?? what can i do to determine what the cause of this high temp/ excess pressure/coolant loss is a resutl of. There are no visible external leaks, changed oil and no signs of water in oil or under oil cap, no white smoke from tailpipe.
Oh ya i live in costa rica so access to good mechanic is scarce.
help!!
Thanks
breck