Scorpio58

Granted I am ignorant about vehicles, however...I seem to believe I have an engine oil cooler problem in my SAAB. I have oil in coolant, but no coolant in oil. It has been at a mechanic's place for three days and I am not in agreement with "possible" head gasket. I just drove the car 800 miles with no incident, no overheating, other than a hose improperly connected and loss of coolant . The hose on the overflow container at the bottom, also is obviously split and it appears the cause of where the oil is going as it keeps registering low oil. The engine light came on and I suspect a pressure related issue unless after getting gas I have improperly replaced gas cap. Any input would be greatly appreciated. I am looking at the first three logical steps which is get the code for the CEL, replace the hose, and test the oil cooler as well as flush coolant reservoir, but I am simply a woman with no automotive background and do not want to insult my mechanic. Please advise.