That $935 seems way out of line, unless there's something unique about that gasket on that particular car. The actual parts look like they're around $80 at the most. I've only ever removed an intake manifold on two cars, and it hasn't taken me more than a few hours to get there.
The intake manifold gasket is the last spot where the fuel/air mixture goes through to get into the engine. The leak should be inconsequential when the car is not running.
The more you drive it, the worse it will get. Running it in that condition will result in oil continuing to leak, which isn't a huge deal as long as you check the oil level often and carry extra to add if necessary. The car also might not run 100% right, but unless the leak gets really bad it shouldn't affect performance/efficiency too much.
So, get it fixed, but it doesn't have to be right away if the leak isn't that bad yet, especially as you drive it so little.