An R9 270x would have pretty good performance. Or a GTX 760, if you want to try nVidia this time.
http://www.bit-tech.net/hardware/graphics/2013/11/27/battlefield-4-performance-analysis/3
Either of those would allow you to keep your current PSU. That's good news, since you can't buy a decent graphics card AND a power supply with the total under $150.
The bad news is, they cost $220 to $250.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814150692
http://www.newegg.com/Product/Product.aspx?Item=N82E16814130953
For $150 or less you can have a R7 260x or a GTX 660
http://www.newegg.com/Product/Product.aspx?Item=N82E16814125477
http://www.newegg.com/Product/Product.aspx?Item=N82E16814133470
I'm not sure those would make you happy. They are better than the HD 7770, but they won't do so well in recent games.
Maybe wait a few months, save some more, wait for prices to come down too?