Upgrading Video Card (Compatibillity/power requirements)

[moneymoh]

I've never upgraded a video card in my pc before, i've never had to before, i'll make this short and simple for you

I have this PC: Gateway DX4850-45cu
http://www.canadacomputers.com/product_info.php?cPath=124&item_id=041020

I heard the power supply in the PC provides 300 watts, it was difficult to find out so i thought id post that here
The video card in my PC is the Nvidia geforce gt 420

Im considering buying this video card (if you can persuade me otherwise for any good reason i wont, (buy a diff one, idk)
EVGA GeForce GTX 560 1024 MB GDDR5 PCI Express 2.0 2DVI/Mini-HDMI SLI Ready Graphics Card, 01G-P3-1460-KR

http://www.amazon.com/EVGA-GeForce-Mini-HDMI-Graphics-01G-P3-1460-KR/dp/B0050I1PHO

I figure i need to increase my power supply too, based on this link http://www.hwcompare.com/10998/geforce-gt-420-vs-geforce-gtx-560/
it says the power consumption for the upgraded video card is 100 watts more and my pc currently has 300 watts,
so should i just go for 400+?
i had this picked out
http://www.cputopia.com/psu-replacement-gate-gateway-dx4850-45.html

is all this good to go? can you offer me any advice, tips, revise anything here, thanks so much in advance

[1LuckyGuy]

Just to let you know, that the video card you picked is actually on amazon.com, not amazon.ca. You would need to pay extra shipping, duties, pay in USD, other problems, etc...it's also not really that great of a price.

I would recommend instead this 6850 card on sale at NCIX right now:
http://www.ncix.com/products/index.php?sku=58225&vpn=GV-R685OC-1GD&manufacture=Gigabyte&promoid=1018

Performance should be close to the 560, and you'll get very good bang for your buck.

If you want to go for the 560, this is an excellent price as well:
http://www.ncix.com/products/index.php?sku=61198&vpn=01G-P3-1463-KR&manufacture=eVGA&promoid=1058

In terms of a power supply, you definitely do not want to buy the one that you posted.
It seems like you might be thinking that you can only put a Gateway power supply into your computer. This is not true. PSUs come standardized, and you can (and should) use a PSU from a more recognized 3rd party manufacturer. They generally are more reliable and have better warranties.

I'm not too up to date on the current deals for PSUs, but a quick check showed me these two, either of which seems like they would fit your needs:
http://www.canadacomputers.com/product_info.php?cPath=33_442&item_id=040842
http://www.canadacomputers.com/product_info.php?cPath=33_442&item_id=038034

[596722]

Before you buy anything you might want to check to see if your power supply is even removable. I know someone who had a gateway desktop (some one with a 2600 from bestbuy) and he had the same idea but couldn't remove the PSU. Apparently gateway attached it in a non-normal way that prevents it from being removed.

[Busybuyer888]

This would also be okay for a Power Supply upgrade. Under $30 for a name brand p/s is pretty good.

http://ncix.com/products/index.php?sku=62331&vpn=VP450&manufacture=Antec&promoid=1382

[moneymoh]

thanks for everyones help, i'll definitely consider everything you've said