Low oil won't affect the fuel pressure i'd have said.

Go to the store and buy a 4 litre can of synthetic oil in the type recommended for your Gallardo, and stick a litre in. Wait half an hour and go out to check the dipstick. Remember to wipe clean before checking again.

If you still can't see an oil level register, take another car. If you *can* see a level, fill it appropriately and then check for leaks.