Buying New Monitor and Computer

[thejerkface]

I've been wanting to upgrade my monitor for awhile now. I currently have a Dell 2001FP. I generally 8-table on it with Party's resizable tables. However, now that Party is shutting down for Americans, I'll be moving on to play on another site. I know Full Tilt and UB don't have re-sizable tables, so having a big monitor will be a big plus. Dell is currently having a sale for the 3007WFP for $1444. So I plan on getting that.

When I buy this new monitor, I'll need to get a new computer as well. I currently have a Dell Dimension 8400. I talked to Dell support and they said my Dimension 8400 wouldn't generate enough power to support the 30" monitor. I was pretty surprised by this as I thought I'd simply need to get a new graphics card. If this is really the case, I need some suggestions for getting a new computer. My computer will definitely need a graphics card that can support dual monitors: a Dell 2001FP and a Dell 3007WFP. I'm not sure what else I need though. I mostly use my comp for poker and internet.

When I'm playing poker, I'd have the following programs running:
Poker program (either Full Tilt, Stars, etc. possibly both)
Pokertracker
Poker Ace HUD
Some AHK scripts
iTunes
Firefox
AIM
Soulseeek

So what should I get? The brand doesn't matter to me and I don't want to spend more than $2k. I've never built my own computer. If it's not too difficult, I'd be willing to try it. What do you think?