Factory vs home build

New build me thinks, this is AM2 socket.
Keep the GTS250-512MB because it's fair.
The Antec Basiq 500 is also good to keep.
Iris-8 motherboard is becoming quite dated now with it's AM2 socket and DDR2 RAM.
4450e could be regarded as an antique in 2011.
The drives you should keep because they're fair and have all your files/data.

What do you use your computer for?

I play games like mafia II, assissins creed 2, grand theft auto v, mass effect 2. and a few others like star trek online etc. also online things like facebook/farmville.

GTS250 should be fine however if you want to take advantage of DirectX 11 (Only in Windows 7) then you should get at least a GTS450 (Around £95 now).

At this point I think almost everyone is talking about saving and building off the sandy bridge platform due the the much faster processor setup and lowered cost of mobo and cpu set ups. In all honesty the amd setups are getting blown away and they are going to be fighting to keep up so it is probably worth it to wait a bit and get a cheaper sandy bridge set up.

Why do you want to upgrade? Is the performance bad? What resolution do you play with?

I'd wait until you start being dissatisfied with performance, then follow the advice above.

^ Very good point.

Usually, if gaming is your thing, look first to your graphics card for an upgrade.

1) Run your games, but lower your resolution and eye candy.
If your FPS increases, it indicates that your cpu is strong enough to drive a better graphics card.

2) Lmit your cpu, either by reducing the OC, or, in windows power management, limit the maximum cpu% to something like 70%.
If your FPS drops significantly, it is an indicator that your cpu is the limiting factor, and a cpu upgrade is in order.

It is possible that both tests are positive, indicating that you have a well balanced system, and both cpu and gpu need to be upgraded to get better gaming FPS.

I run all games except black ops and gta iv which lags a bit, but playable. I love my system but I just keep seeing on Can you run it, some games are saying to upgrade the CPU. and my mother board cant increase too much only like up to a 4800 and thats like 200 mhz extra and wont see an improvement by much, so I was just asking if keep this, or upgrade motherboard or new rig time. but I am happy for what I have

What's your budget? Those branded PC's aren't really worth upgrading. Just save up and build new. i5 2500K / P67 / GTX 460 / 4GB DDR3 for about $500

thats why I was saying I upgraded everything but the motherboard and processor. dont know If I should get new motherboard and cpu or just a new rig dont want to go over 500

Well, if you stick with AMD, then you can do it for about ~$250
CPU: Athlon X4 645 $110 http://www.newegg.com/Product/Product.aspx?Item=N82E168...
MB: ASUS $85 http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Ram: $55 I picked something random http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Total $250

Edit: Sell that 4450e on ebay. Those low powered CPU make great media PCs and were once in high demand.

so I can just get a new motherboard and cpu, not a rig and I dont have to get a new hard drive/operating system right.

Well, a new OS is assumed when getting a new motherboard.
You're going to have to re-install your OS when you get a new MB.
Might as well get new Hard drive while you're at it too. A Samsung 500GB F3 or 1TB F3 will do you good.