I dont think upgrading your laptop's ram would be sufficient. sadly laptops allow for very little wiggle room when upgrading and I think it might be more gpu/cpu related instead of memory. Honestly though, if you see yourself playing PC games for awhile, I suggest investing in a desktop. If you build it yourself (building a computer is no where near as hard as it sounds), you can make one pretty cheap that will run most games on high/ultra.
There ya go man. And I would suggest, if you're short on cash, go with an amd processor. They cost way less, but I have had both amd and Intel systems and never encountered a problem. If you've got cash to burn, however, then go with an Intel core i7. Intel CPUs generally perform better on benchmarks than amd. Watch the tutorial videos at the link above and you'll see that building a PC is really quite simple. And will run you about 500 bucks, as compared to an equivalent, prebuilt system that will run you about double.