foxconn does indeed sucks. However, I see no reason you can't get a cheap graphics card.
9600 GT - $65 after MIR, today only. It's more than powerful enough to play End War, but you'll be struggling through some low graphics. It will run just about anything, just the newer stuff won't run very well. It's an EoL product,
so only get it if you really need the graphics and gathering money is going to be difficult/take longer than you want it to.
Power consumption isn't bad either. Using a better setup, they're getting ~200 W max. Add a bit of an overhead on that, and I'd be comfortable with even a 350W PSU. Make sure you check though before you ever upgrade a computer. If you experience system instability, get a better PSU. Seasonic/corsair/silverstone/antec earthwatts/enermax/hec(I think) are all good quality PSUs, and there are many more. Just don't get rosewill or something that looks too good to be true. Then again, I have a free 500W PSU which served me well for a long time.
Also note that you can't really overclock prebuilt computers without flashing a custom bios (something I wouldn't want to do). That makes Ex's complaint on the sucky motherboard moot. I'm assuming that the 630i chipset has a PCI-e x16 slot needed for graphics, and foxconn actually put it in there. You won't know for sure unless you open it up and check, though.
Building a computer is like a really expensive lego set with 12 parts. It's not hard at all, and if you do it once, you'll learn so much about computers in general that you'll start to hate everyone who ever thought that computers are "too hard".
If you can re-use your: case, optical drive, hard drive, that leave you with replacing RAM, PSU, cpu/mobo/gfx. $400 is easily manageable to get a kickass system. You'll need to procure your own OS though. Eventually you'll want to upgrade that Hard drive and case, though. The nice part about cases is they never really need to be replaced, so you really only want to ever buy a good quality case. Hard drives shouldn't last much more than 5 years.
"Parliamentary inquiry, Mr. Chairman - do we have to call the Gentleman a gentleman if he's not one?"