Need help upgrading Alienware

First off my budget on this is not set in stone so I would like cheap to medium stuff.(I need everything Minus the cooler and case upgraded)

this is the aurua I have - http://i.dell.com/sites/content/products/PublishingImages/desktop-alienw...

I also have this liquid cooler - http://i1-news.softpedia-static.com/images/news2/Asetek-Liquid-Cooling-S...

OS - Windows 7 Home Premium

CPU - Intel Core i7 920 @ 2.67GHz

RAM - 9.00GB Triple-Channel DDR3 @ 668MHz 

Motherboard - Alienware 0H869M

GPU - 1792MB NVIDIA GeForce GTX 260

Sound card - Creative X-Fi PCI Express Sound Blaster Xtreme Audio Sound Card

You could just upgrade the GPU, that will give your system a new lease of life. The i7 920 is still a relevant gaming chip.

Is there any specific requirements that you have?

I just want the parts to be compatible and that it can game good/render videos

I know at least a couple of popular YouTubers that use the i7 920 to render videos at this current time. Grab a GPU like a 7950, while they are cheap. It will more than double your performance in games, contribute a good amount to editing, and it will all be compatible.

Ensure the power supply is good.

Try that first, before you spend lots of money on hardware.

GPU and an SSD (depending on sata) maybe. Would improve performance a fair amount.

Is that compatible with he other stuff like my motherboard?

Yes, I checked that your motherboard has a PCIe gen 2.0 slot. Just ensure that your case has enough clearance. Some AMD cards can be very long in length. If you're unsure, you can ask in the forums.

Can you leave us a little detail on the PSU? I just want to make sure that is compatible.

If you have used the PSU for some years, you might want to change it before it blows up.

Maybe add more RAM? I mean 9 is okay its enough for rendering but if you multitask like me you might want to get 16