PSU/Video Card Question(s)

This is my first forum post (Hello!) and I have a very important question to ask you folks.

I'm currently looking to buy this combo deal from NewEgg which includes a NVIDIA 9800GTX+, and an Antec 500W PSU, and then I'm also buying 2 gigs of RAM.
http://www.newegg.com/Product/Comb [...] mbo.194122

I have no idea if either of these things will fit in my current setup. I have a Gateway 840GM (one PCI-E slot) and the case is pretty cramped (Two stock fans).

So if you could tell me if the card and PSU will fit into my case, I'd really appreciate it. Or even an exact measurement for the card would be fine so I could measure it myself. I will provide a link to a few images of the inside of my case for some additional help. Don't mind the dust either, I have since cleaned it

http://i40.tinypic.com/2331gh.jpg
http://i40.tinypic.com/2ns5l4m.jpg
http://i39.tinypic.com/28vvzlv.jpg
http://i41.tinypic.com/a123xu.jpg

Thanks again!

Forgot the PSU, it does look alot like ATX. So it'll probably work fine.

Can you take up the CPU heatsink and take a picture? You might be able to change the heatsink. My BTX Dell can't because it has capacitators in the way of a AM2 bracket

The HD 4850 should be performing close to the 9800GT. It might actually bee a tinsy bit better not entirely sure.

EDIT: Sorry guys for the triple post, I forgot

I'm looking to keep this at $190 or lower, as I need to buy Starcraft II when it comes out, and Team Fortress 2/CS:S.

EDIT: Okay, if it was these three choices, which would fit my case, perform the best, and have a good enough PSU all at the same time?

http://www.newegg.com/Product/Comb [...] mbo.185373
http://www.newegg.com/Product/Comb [...] mbo.194122
http://www.newegg.com/Product/Comb [...] mbo.187268

EDIT 2: Or show me a card/PSU seperately, under $190, thanks!