Your upgrade plan looks OK, because you are very RAM short. IGB is just barely enough to run the OS let alone a game.
But in case you are still thinking about a possible replacement for something with better growth potential, there are some decent after Xmas sales. For example I saw this one at CyberPowerPC
I like Cyber Power because they are one of the few that lets you selecy brand. not just type of RAM etc. This model is CrossFire ready it you want to go full bore for the price od a 2nd GPU.
Socket AM2 AMD Athlon X2 6000+
(Free Upgrade!) 6X Blu-Ray Player / DVD+-RW Drive
Just an idea I toss out for you to consider.