[Build Help] Graphics card upgrade now or wait

Hello,

since my current build (put together by a friend) is a little over 4 years old I've decided I need to upgrade my graphics card. You can see most of my build below.
My current graphics card is: POINT OF VIEW GeForce GTX570, TGT Ultra Charged (couldn't find this specific model on pcpp)

I want a decent card that will last me a few years. After a bit on research I decided on the MSI GeForce GTX 970 Gaming 4G and I think it is compatible with my current setup.

I play mostly Dota 2, but I definitely will buy Rise of the Tomb Raider and XCOM 2 in early 2016 (and probably some random games in steam christmas sale).

Now to my questions:

1. Do you think I should buy it now or wait until january/february? I am not well informed so there may be something better out by then?
2. Is MSI GeForce GTX 970 a good choice? It seems to be a good card for this price range (I don't want to go a lot higher)
3. Should I also upgrade my CPU? I'm not really sure if it will be a bottleneck for newer games.

Any help is greatly appreciated!

PCPartPicker part list / Price breakdown by merchant