Subaru Repair: 91 subaru loyale 1.8l possible head gasket?, oil pressure guage, subaru loyale

Question
hardly no power on flat and barely goes uphill. tune up done no improvement. rpm tach guage fluctuates about a tick (bounces slightly) oil pressure near 0 when idling. driving oil pressure guage is half way. my mom had someone do a tune up before recent one and the dummy put oil in the radiator. it got flushed out 3 times she said manually i believe by the petcock valve. the radiator fluid is clear green. doesnt lose much fluid. maybe a couple inches in neck after 50 miles or so. oil is good. it runs rough like a misfire and idles rough. sound like a head gasket?  i am not sure if it was driven with oil in the radiator.  thank you

Answer
Ok oil in the radiator is bad for the hoses over time but isn't going to cause any damage to the head gaskets.  Especially right of the bat.  

There are many things that can cause a misfire or running poorly including a failed head gasket.

There isn't much I can do over the Internet to diagnoses what is wrong with your car.  There are many things to check and rule out prior to blaming the head gaskets