Have you tried cleaning up the engine yourself, and then positively identifying the location of the oil leak? There are not that many places for leaks that are common. It's likely one of those. I'd not assume that the oil leak is related to the running issue yet. The Optispark unit might be on it's last legs, but it does not need oil inside to be defective. Just bad luck and time.
A detail shop should be able clean the engine up without damage to electronics for about $100, which is what any good mechanic will charge you to poke at the car for 1 hr. If you clean the engine, and then place a large clean sheet of paper or cardboard under the car overnight, you may be a lot closer to locating the leak by morning.