BMW Repair: oil pump, oil pumps, dip stick

Question
QUESTION: went to garage to put petrol in car ,red oil light came on put a small amount of oil in car check dip stick good amount of oil in car had to get home ,drove car 100yards stopped it as bag of bolts sound came off of it phoned AA he said it sounded like it was my oil pump wasnt working and there was know pressure . my friend who is a mechanic says cost wise replacement engine would be the best option as if the opened her up and there was more problems it would cost a fortune could you please advise me on the best option thanks

ANSWER: Would need more information, what car ,engine year?????????????

Tony

---------- FOLLOW-UP ----------

QUESTION: the year of the car is 2003 3i8 ci sport cabrolet

Answer
Not aware of any issues with oil pumps on that engine.
If you only drove it 100 yards with the light on then minimal damage has occured if your lucky.
Drain the oil into a clean container and observe it looking for metal and the like.(swarf) is the technical term.
If ok , and it probably is, remove the oil pan (sump) paying special attention to the gaskets.replace the pump and hopefully all ok.