New Computer Parts help? Very, very mild gaming computer.

I have a Dell Optiplex 360 that I bought for 50 bucks from an office sale. I stuck in an extra 2gb of RAM and I plan on "acquiring" Windows 7 64 bit so I can take advantage of that RAM. I also plan on getting this GPU for it right here. Just to let you know, this computer only has a stock 235 watt PSU and I am not going to upgrade it. (not worth it)

Any suggestions? and do you see any problems with this build? I want this computer for the following games primarily:

Minecraft/Tekkit/Many modpacks at once
Counter Strike Global Offensive
Garr's Mod (lots of addons)
Battlefield 3 (Possibly)
Space Engineers
Dayz/Arma 2

Could you please list an estimated FPS I would get with this build on these games? Please leave detailed answers <3 Thank you

@lordfuhnee: http://www.amazon.com/EVGA-Superclock-Dual-Link-Graphics-02G-P4-3753-KR/dp/B00IDG3IDO/ref=sr_1_5?s=pc&ie=UTF8&qid=1417573266&sr=1-5

Or you could get that

Battlefield 3, Day z, arma, garrys mod and possibly counter strike will be almost un playable.. I'm guessing with that psu it has a complete crap CPU.. it was an office purpose PC so it never had hardware capable of gaming.

I doubt anything besides minecraft runs on it, and if you plan on modding the crap out of it.. well you may have trouble with that as well.

After looking up the benchmarks of the CPU.. yeah don't expect much from that thing.

do you think the cpu bottlenecks that at all?

The OptiPlex 360 came with 10 different CPU's available, from a Celeron 440 to a Core 2 8600, without knowing exactly, I recommended the best GPU that doesn't require any additional 6 pin connectors.

I'd be going with this as well - GTX750Ti

But lets say for a second that you decide to go with that old GPU (6450):

as you can see on lowest settings, you can forget about BF3. and that's not even 1080p.

and don't forget you have there Core 2 Duo while the benchmarks are with i7.

I'd say forget about gaming with that PC at all.

You'll want to spend 80$ on a CPU at least, 4-8Gb of RAM (30-70$) and a brand new GPU 100-150$ (GTX750/Ti)

just buy a pci-e motherboard for gaming. its the least requirements if u can assemble the rig by yourself.

What?

Find me a consumer mobo without PCI-e.

... A computer purchased from an office sale with a low end GPU isn't a mid range or even a low range gaming machine.. Stop being cheap as **** save some money and buy $600 bucks worth of parts and walla, A computer to last you 5 years instead of some piece of shit money sink you've got yourself into.