Oil change. Perform Service light on

As long as it will run.

Do it at your first opportunity.

How long you can drive it would depend on how much you like the car. Your car is constantly heating the oil and slowly burning it up which at sludge to your engine. You want to keep it as clean as you can (reasonably of course) to preserve your engine which is a much much larger expense than an oil change. All that being said, just get to the shop as soon as you can but most likely your car wont suffer too much if you need some time to get your affairs in order :D hope that helps