New Graphics Card and PSU

My 12 year old son has a Compaq HP SR2180NX with integrated graphics. I have upgraded his RAM, which improved performance but his graphics card sux. I am assuming he will need a PSU upgrade as well.

I want to upgrade his video card to allow him (and me) to play current games.

I have read through many recent posts and searched online to try to make a decision on the best card and have learned enough to know there are a lot of factors to consider. I would appreciate if you could recommend a card +/- 100 dollars, and a PSU to drive the card. Based on my online research I was leaning toward a 8600 GT but have no clue on the PSU.

From what I have read, cooling is another issue to consider. Can I simply buy and install a card and PSU, load drivers and start playing with the new gard or will I need to add fans, etc to make things work? Will any card fit in the case? Will I need software to control the fan speed? Is the new card plug and play or will I need to disable the onboard integrated graphics card?

Here are specs on his Compaq HP SR2180NX:
Windows Vista Home Premium

Intel Pentium D, two processing cores, (2 x 2.8GHz)
Case (outside measurements) 7W x 16D x 14.5 H
PCIE, 1 x 16
3 Gig RAM, DDR2 PC2 5300
Factory power supply 300W, 19A on 12V rail

Any recommendations or additional considerations are appreciated.

MSI R3650-T2D512 OC Radeon HD 3650 512MB 128-bit GDDR3 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card -

http://www.newegg.com/Product/Prod [...] 6814127331

CORSAIR CMPSU-450VX ATX12V V2.2 450W Power Supply 90 - 264 V UL, CUL, CE, CB, FCC Class B, TUV, CCC, C-tick - Retail

http://www.newegg.com/Product/Prod [...] 6817139003

Most likely this card will also run on stock PSU, but in case you want to upgrade to a good affordable unit that can handle most cards out there...

It is? I read a review this morning saying it was an Okay card. I just can't picture AMD bringing out an HD 3650 only to be beat by their own HD 2600XT which in turn I believe it's a stronger card than the 8600GT.

You might be able to push that psu and if you can shell out more money, get a 3850.
But 19a sounds a bit low so I would be safe and stick with a 2600xt.

The 2600xt which will perform around a 8600GT and cost lower.
http://www.newegg.com/Product/Prod [...] 6814102708

Aren't ATI releasing a 3670 to bridge the gap between the 3650 and 3850?