Need help updateing my Alienware (its really old)

First off my budget on this is not set in stone so I would like cheap to medium stuff.

this is the aurua I have - http://i.dell.com/sites/content/products/PublishingImages/desktop-alienware-aurora-hero-504x350.png

I also have this liquid cooler - http://i1-news.softpedia-static.com/images/news2/Asetek-Liquid-Cooling-System-Inside-Alienware-039-s-Latest-Rigs-2.jpg

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

 

What are you looking at upgrading? 

All of it besides the case and liquid cooler

 

You may need to get updated mounts for your cooler to mount to a new motherboard wiht an updated socket.

Cheap to medium? Not sure what that means. Cheap could mean 400 bucks and medium could mean 800. Do you have a range?

Are you keeping the same power supply? What's the wattage? Do you want new storage?