Power supply and video card recommendations

[InkLill]

I was recently passed down my first desktop: a crappy old HP Pavilion 6200n. I am big into PC gaming but am fed up with having to use a shared, slow computer or my terrible laptop.
I am planning on beefing up this system instead of starting all over with a new one. I am upgrading to a NZXT Tempest Evo case, and the first things I will do is new RAM, a video card, and a power supply.
I want to upgrade the power supply first. Right now I am using a stock power supply, only 250W. A cheap quality powersupply, around 400-600W (enough to support a midrange video card) is what I am looking for, preferably no more than $100USD. Suggestions?
I am also looking for a good gaming video card...I dont need any fance SLI or crossfire or whatever it is...but something with at least one HDMI output and capable of supporting 2-3 monitors.
If you need any extra specs just tell me specifically what you need and Ill post them.

 

[Leeky]

Before you do anything, what CPU does it use?

Will be pointless even considering a new midrange GPU if your CPU is just going to bottleneck.

 

[InkLill]

CPU Specs

Before you do anything, what CPU does it use?

Will be pointless even considering a new midrange GPU if your CPU is just going to bottleneck.

It is (according to system properties and the side of the case):
AMD Athlon 64 X2 DUal Core Processor 5000+
clocked at 2.6 GHz

 

[JMMD]

Power supplies can be used from machine to machine so get something that will last. I would recommend:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139005
or http://www.newegg.com/Product/Product.aspx?Item=N82E16817371015
and for a video card, maybe an Nvidia GTS 450 or AMD 5770

 

[hellokitty[hk]]

Tough call, but I'm thinking the best you can do while supporting that many monitors is a Antec Earthwatts 380D and a 5670 or so.

 

[Rage_3K_Moiz]

What's your total budget for everything?