PC Upgrade Advice

Hey everyone, I'm looking for some advice here. If you could lend a hand, I’d really appreciate it.... So, I picked up a new rig a few months back, and here's what I'm running:
http://www.igreklik.com/slike/images...7861198457.jpg
I have this nephew who's been over at my place constantly lately because he claims my setup is way better for gaming.... He's got this machine at his house:
http://www.igreklik.com/slike/images...5344047433.jpg
It’s about four years old now. He mentioned that if he had bought the same graphics card I have and popped it into his build... or maybe even just buying this specific card right now...
I couldn't really give him any solid advice because I don't know the ins and outs of this stuff... especially regarding that card from $100... Honestly, I suspect his PC wouldn't be able to handle a card like that given his other components. The main question is: what's the best way for him to beef up his rig? Gaming is his absolute priority. Is just upgrading the GPU enough, or is there more to it? He’s got a pretty big screen at home—basically a TV set at 1920x1080 resolution. What would be the smartest move in his situation? Any advice is welcome... thanks in advance.

If he grabs that one, it's identical to yours and should pair perfectly with his processor. Honestly, though, you can find GTX 750 Ti cards for barely $333, so $433 seems way overpriced to me. If he isn't set on buying from Links, maybe check this out:

One little plus is that both cards have really low power draw, so he probably won't even need to swap out his power supply if his current one is a bit of a junker.

It’s impossible to tell what kind of power supply is in that shot...???
He took some more photos, so maybe one of these will actually show us the PSU....
http://www.igreklik.com/slike/images...0845325613.jpg
http://www.igreklik.com/slike/images...8674156457.jpg
http://www.igreklik.com/slike/images...1322019211.jpg
http://www.igreklik.com/slike/images...7992646217.jpg
http://www.igreklik.com/slike/images...4100325454.jpg
http://www.igreklik.com/slike/images...3906487476.jpg
http://www.igreklik.com/slike/images...5223648128.jpg
http://www.igreklik.com/slike/images...1727433262.jpg
http://www.igreklik.com/slike/images...7609785417.jpg
http://www.igreklik.com/slike/images...7051332994.jpg
http://www.igreklik.com/slike/images...7091511123.jpg

Software won't give you a clear look at the power supply's health, so just stick with what you have. That GTX 750 should be more than enough to handle the load, especially since the CPU isn't built for anything high-end anyway.

Alright, here’s another one for you... someone actually suggested he should go out and buy more RAM, as if the 4GB he’s running right now isn't basically nothing. They told him more is always better. Is it actually worth throwing money at this?

Not really, I’m running 4GB so I can actually have two games open at once along with Chrome, Skype, and a few other things running in the background—I hit 3.5GB once before.

Btw, it might run a little slower (though hopefully you won't notice) if there's too much free RAM.

It sucks that there are only two RAM slots on that motherboard, so if he wants 8GB, he’ll probably have to ditch both sticks.

I guess 4GB might get him through for a little while, though.