4year old Dell, new computer or just card?

Step by step process.

1. Ebay dell.

2. Build new comp with dell $ and other $s that were previouysly going to be used to upgrade.

3. end up with better comp.

4. fold  

Ta-Da! WIN!

Thanks Andrew. Anybody else have any thoughts? Thank you.

Last bump before I give up...

If the processor is a single core, I would recommend building yourself a new computer, It may cause bottlenecking from a newer graphics card. Also I'm not sure how strong your power supply is but if its the stock one that came with that computer, You might want to forget about the upgrade unless you're getting something real cheap.

If you're going for a new computer, Check out the barebone kits from Tigerdirect's site, Got some decent deals going on.

Edit: After a quick look around, Apperently the GeForce GTS 450 only requires a 400w power supply, Take a look at the wattage of your power supply, Maybe i can help you find a card.

If you're going for a new one, This barebone kit includes a Phenom II X6 for $335 (300 after rebate) which would leave alot of money for a graphics card of your choice http://www.tigerdirect.com/applications/searchtools/ite...

Go for a new machine. You can get a decent quad core gaming machine built for ~$500, ~$600 with OS.

CPU: Phenom II x4 955 BE $109.99 ( with code )
MB: Asrock 970 Extreme 4 $104.99 ( am3+, Sata 6Gb/s, USB3, Crossfire )
Memory: Corsair XMS 2x2GB 1.5V 1600Mhz DDR3 $39.99 ( before $10 MIR )
GPU: Radeon 6770 $119.99 ( before $20 MIR)
HDD: Samsung Spinpoint F3 1TB $54.99 ( might be still 49.99 with code )
DVD: Sony 24x DVD+/-RW $18.99
Case: Thermaltake V4 black edition $39.99 ( with code before $10 MIR )
PSU: Antec EarthWatts 430W $44.99 (with code)

Total: $533.92 before MIR ( $493.92 after )

+ Windows 7 home premium 64-bit $99.99 if needed.

Thaghost, thanks for the info. I will post the complete system specs when I get back home in a day or two. If I can get another year or two out of this system for less than a hundred bucks that's what I will do.
I'm not sure I want to get a decent gaming rig for $600 that I would need to upgrade in another year or two. So it really comes down to me milking this one along for cheap or buying a system that will cost closer to 1,000 and lasting longer.

I was generally just trying to point out that at the $500 price point you can get a viable build. Naturally at $1000 you will be able to get pretty much the optimal performance available these days including a i5 2500k and a GTX560Ti or 6950.

I appreciate you pointing out the options rvilkman, I've been impressed with how many helpful people there are on this site.
Here are the specs:
Intel core2 quad cpu q6600 @2.4
NVIDIA GeFOrce 8800 gt
4gb ram
Windows Vista Home Premium
Board: Dell Inc. 0FM586
Serial Number: ..CN736047CU01CA.
Bus Clock: 266 megahertz
BIOS: Dell Inc. 1.0.15 06/20/2008

dont bump posts, you need to sell your rig and start building new imo, I wouldnt go much higher than an 8800 gt on that system, also; get win 7 x64.... You can put together a really nice i52500k gaming rig for around 800 bucks if you do not go overboard in other areas.. but certainly (like rvilkman stated) an i5 2500k and a gtx 560ti/6950 is a great starting point.