1. upgrading the laptop - not likely. Some laptops have replaceable GPUs (like the MSI GTs and Clevos, including the iBuyPower CZ-17), but it won't be too cost effective.
2. You don't have to change whenever new hardware is available, but when your laptop is no longer holding its own.
3. Remember - the current situation is that manufacturers make the components in a way they usually perish after 3-4 years.
Thanks for the response! I've been looking at the Eurotech racer 2.0 and it looks like it may be just what I need. Thanks for the heads up!
4. If you can live with medium-high settings for 2-3 years, I'd go with the GTX 675MX CZ-17 or the Eurocom Racer 2.0 with Radeon 7970M. Really, you can't do much better than that. Yes, there are dual GPU laptops, but that is currently not too effective in the high end part. Such laptops will be also very heavy and battery is just to keep the laptop alive for a short time
I really think you should take a 1300$ laptop top and manage with it for 3 years. You can always clone your HDD later to some new SSD in a new laptop.