I have a 1080P Monitor and a 1000w PSU, an Intel Core 2 Duo CPU @ 2.33GHz, 2.00 GB of RAM and Windows 7 Ultimate SP1 does this help?
Yes, that helps a lot.
You don't need to buy a new monitor. And you don't need to buy a new PSU.
And probably not a new case either. It depends a bit, if the case and PSU are standard ones. I believe companies like Dell and HP sometimes use non-standard cases and PSUs and other components. But you are probably safe.
And you can reuse your Windows license. That more savings.
Now you could buy just a new videocard.
That depends if your PC is new enough to have a PCI-E slot, and not an AGP slot. (90% sure you must have PCI-E).
But like Deaths_soul says, your CPU is 5+ years old. And it will hold back Skyrim (and other games and applications).
In any case, you need more RAM. 2GB isn't enough to play vanilla Skyrim, let alone use mods.
So the choice is: a) only a new videocard, that would set you back 200-300 dollars.
Or

new CPU, motherboard, ram and videocard.
Option

will have you covered for another 3-4 years at least.
But it will cost you the $600 I mentioned earlier.
New HDD is $50-$100. Might be worth it if the old one is slow or small. Personally I don't mind buying a new HDD every few years. Less risk of failure and losing data. If you don't have a DVD-player, you might need one for easy installation of software or games. Only $20.
Check the web for "buyer's guides". There are many of those.
Here is an example: http://www.anandtech.com/show/5184/holiday-midrange-system-buyers-guide/3
But remember: Intel i5-2500k cpu, z68 or z77 motherboard, 8GB of ram. And a videocard in at least the $200-$300 range for good gaming.