I would like to know what graphics card is necessary for my needs

Hi, I'm SeReNiTY. I am a current PC/Mac gamer and plan on building a PC within the next year (I don't really have a money-making medium).
I am typically playing games such as Half-Life 1, Team Fortress 2, StarCraft II, and plan on buying Counter-Strike: Global Offensive and Portal 2 in the very near future. I want to save as much money as possible without restricting myself from new games due to hardware restraints. What graphics card is necessary to play these games at their maximum settings, while still being able to play games like Battlefield 4 at low/medium settings if I so happen to buy them? Also, if you can direct me to a decent build that will do this for cheaper than $400, link me to it.

Thank you for your time. If you happen to be interested in playing some Team Fortress 2 or StarCraft II with me, I can be added on Steam as Ambassador Pineapple (thumbs up if you get it), and on Battle.net as SeReNiTY. Thanks again.

get 7970 off the ebay its going to be base of your pc; rest can be weak. (most games do not need as much of cpu as gpu)

Here is what I came up with for close to under $400 if you wanted to buy all new parts:

If you are comfortable buying used, you can pick up a Radeon 7850 for under $80 that will give you close to 270 performance.

How weak are we talking?

Thanks for the build. It gives me insight on what to buy.

We are talking about going for AMD quad core. 7970 will run most of your games at 1080p at high detail in playable environment. (you can buy it as new 280x or used from ebay where prices will be around 100-140$)

I will be going for the eBay option.

So you're talking about something like a Phenom or Athlon, or an APU?

You'll be fine with whatever depending how good are you on costs i'd check review for cpu you want to buy before hand. See how it fares. (still no point going on intel as its much more expensive for what you're getting) (apu, computing cores are going to be little slower) maybe if you feel like going for 100$ cpu i'd go for http://www.newegg.com/Product/Product.aspx?Item=N82E16819113286

here are 2 examples of 2 good offers for the moment on ebay.

but basically you need to wait and find really good deal... maybe i'll consider selling off my asus 7970 matrix for 100$ or something.