Graphics card driver?

So for the longest time I've been able to play StarCraft II without too many problems. But since I updated to El Capitan, the application keeps crashing. I contacted Blizzard about this, and by examining error logs they were able to deduce that there were errors coming grom the graphics card (GeForce GT640M). They also said the current version of the driver was 10.6.42, when nVidia has rolled out drivers 10.18 and beyond. Is OSX severely behind on gpu drivers? Is there any way to update these drivers? Anything else I can do to stop this from happening?

Thanks in advance.