Laptop for Total war games

Hello all. I am a huge fan of the total war games and currently a college student. I was given a mac for college.. can't complain because it was given to me however I have been stuck on the mac version of Rome Total war. I have saved for awhile and am going to buy a gaming PC almost entirely for Shogun 2, R2TW, and I plan on playing past games such as medieval (as a huge lord of the rings fan can't wait o try that mod) along with empire. I also want to be able to play any future TW games that come out. I may also put a few other games such as Civilization and I may try some other games. On a few other tech forums everyone is telling me the Sager NP150 with an upgraded graphics card to the 680 is what I need. However when talking to a friend who games on his laptop, he said he thought his 900 dollar dell would handle the games just fine and 1700 is too much to spend. I tend to agree I would like to spend less (around 1200) but I want the laptop to last awhile for future TW games and play R2TW and Shogun 2 on the highest graphics and for it to run smoothly. Any recommendations or thoughts for gaming laptops? is 1700 too much? Also you may need to spoon feed me info as I am a complete novice on the topic.