$300 budget. Need advice

Hey guys, so here is basically what I am looking for.

Something that will support 4 monitors at 1920x1080. It will be 3 24inch acers and 1 27inch. The 3 acers are the 120hz version and the 27inch is a 75hz.

I won't be using 3 monitors for gaming. I will be using 1 monitor to play a game and I will have web browsers open on the extra monitors. Most likely youtube or a game guide, etc.

Games I will be playing are LeagueofLegends, Dota2, Heroes of Newerth, Starcraft2, Diablo3, Counterstrike:Global Offensive, BF3, COD:Blackops, Assassins Creed, Batman, Just Cause 2, GTA5(when it comes out), Sleeping Dogs, Farcry3, and others.

I read somewhere that sli 560 ti's gave a 40% fps increase on bf3 whereas sli gtx 580s only gave about 12% increase. This definitely leads me to believe the 560 ti's are a better "bang for the buck" than 1x 580. But those are the old cards.

I was looking into the 78xx series but I heard that they have had issues with crossfire drivers or something.

the 680s, 670's, and 79xx are out of my budget range.

So far my top choice is either 2x560ti's or 1x 7850 and upgrading to a 2nd one in the future. But I really would like to learn more about whats out there on the market today before making any irrational decisions. I already bought a 3570k without reading up on it and turns out that many ppl said 2500k is better for overclocking and gaming because it stays cooler. I'd prefer not taking the path of buying a card now and upgrading to a 2nd one later, but I am still open to that option.

Whatever you guys think I should do wtih $300, I will most likely do, so please give me some logical reasoning as to why I should go with a certain card(s) over another.

This is an example of a post that will provide zero help: "AMD 7950 is better than gtx xxx" or " GTX xxx is better than AMD XXXX".

That being said., here is my current setup so far..

Motherboard:
ASUS P8Z77-V LK

CPU:
i5 3570k (stock cooler)

Memory:
4x4 GB DDR3 1600 Patriot Viper

HDD:
Western Digital Caviar Black 1tb

Power Supply:
Rosewill 1300watt power supply (the one with all the different colored lights)

Case:
NZXT Gamma Mid tower

Current Video Card:
Asus GTX 550ti  

All of these parts are new except the 550 ti.