There are some PCI cards here. I presume you really mean PCI versus
the latest PCI Express x16 cards ?  PCI is 32 bits at 33MHz for
a total bandwidth of 132 megabytes/sec. That is 1/2 the bandwidth
of AGP 1x.

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2010380048+106960964
2&Subcategory=48

I'll start with the most expensive and work down.

There is an ATI based X1550 there for $129. I would probably
select HIS over Diamond brand, as one Diamond customer had
trouble contacting Diamond for warranty service. No matter
what HIS does, they cannot be any worse than Diamond.

http://www.newegg.com/Product/Product.aspx?Item=N82E16814161074

The Diamond card is a regular profile and doesn't use the dual
faceplate concept. The HIS used a dual faceplate, because it
is designed to work in a low profile HTPC, as well as use
its replacement faceplate to work in a regular height PCI
slot (it comes with interchangeable faceplate). This Diamond
card is $87 after rebate, or $107 if the rebate never
arrives. (Actually, this advert says the video memory on the
card is 128 bit interface, while the HIS is 64 bit, so this
is actually the better card. Forget the other one :-) )

http://www.newegg.com/Product/Product.aspx?Item=N82E16814103031

That is the best of the lot. I think the Nvidia cards left
in the list, would be less than the X1300, but not by
much.

Since you mention Oblivion, I had to start at the top price end
of the list. Even still, you'll likely need to drop the detail
level pretty low. A PCI slot cannot perform miracles.

There are benchmarks in the second link. An X1550 is basically
a rebadged X1300, as described in the first link.

http://en.wikipedia.org/wiki/Radeon_X1000
http://www23.tomshardware.com/graphics_2007.html?modelx=33&model1=740&model2=722
&chart=294

The X1550 looks like it might be about 2x the speed of a 9250,
as near as I can guess based on core clock and resources. Would
Oblivion at 5 or 6 frames per second be playable ? I don't know
the characteristics of the other games, but I hope they are
a bit less demanding. Most of the video cards I've ever owned
have been "slide show" cards, so I don't envy you trying to put
"performance into a PCI slot".

Oh, did you talk to Dell about your other card ? Did they
suggest disabling the built-in graphics, via a setting in
the BIOS ? Also, when you booted to a black screen, did you
try the monitor cable on both the built-in graphics connector,
as well as the 9250, to see if the image was available on
either output ? I'd have a look in the BIOS and see what
video related settings are available. (Based on a previous
posting of yours I found.)

   Paul

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ih=012&sspagename=STRK%3AMESE%3AIT
&viewitem=&item=220104548903&rd=1&rd=1

That should do it for you.

PCI cards (Not PCI-E) are too underpowered to play Oblivion well, regardless
of their low price.  You need at least an AGP card, and really a PCI-E to
see the eye candy graphics.

FX5500 or Radeon X1550, along with this patch:
http://www.oldblivion.com/index.php