piston or valve??

Hi Tom,
I have a 1995 993,...recently in freeway when i was driving,the engine was kinda shaking and stopped so i had the car towed to my personal mechanic.
he told me that my car has little oil in it...so i change the oil but it still won't run....it can be started but the engine would shake and you have to put the key into the ignition for 10 seconds before it can actually start and shaking.
my mechanic doesn;t know anything about porsche but he thinks that one of the piston is gone and 3 of the valves also in trouble.he found this by measuring the three valve.....one has 150 degree but the other three is 100 each.
he still doesn;t know how to fix it and he also not sure about the problem...i duon't want to bring to dealer because iam afraid they will suggest me to replace the engine and that their cost would be very expensive.
i can't do anything becasue i can't drive the car....it has to be towed if i want to move it around.
can you help me with these?..maybe you can give me a solution or diagnose what might be the problem here??
thank you so much for your help.
Sincerely
BOBBY

Your best bet is to take it to a shop that deals with Porsche, it might be cheaper in the long run. If you do need a new motor, hopefully not,you can always sell your old motor running or not. Good luck