doesn't matter who puts them in there, the GMA900 and 950 are nothing, a GMA900/950 will play but struggle greatly at those titles, and a GMA965 will barely play those titles at the lowest resolution.
Look at the GMA950's performance in HL2 here;http://www.anandtech.com/video/showdoc.aspx?i=2427&p=4
The GMA 900/950 in HL2 on a pentiumD platform;http://www.hothardware.com/articles/Pentium_D_820_and_i945GP_Chipset_Showcase1/?page=3
Not stellar to say the least. Sure you know that the game you loaded, but for an FPS, 10-20fps avg is no good.
The GMA965/X3000 is the bare minimum IMO, and only since the driver update (before that it was worse than the GMA950), and really for any type of gaming since the D3/HL2 release should be on at least a low-end dedicated chip IMO.
There are a few sellers of MXM cards, check the notebookreviews forum, there's a guy who sells them and links to other sellers, it's been a while since I've been there so you may have to look a bit.