The problem is that Fallout 3 does not recognize integrated graphics. There is a way around that by installing a d3d9.dll file that was originally developed for Oblivion so that you can run that game with an underpowered video card. See link below to download it.http://www.oldblivion.com/sm/index.php?topic=6928.0
I have tested this on my laptop which has i5-2410 CPU with the Intel HD 3000 integrated graphics core (same in your i3-2310). My laptop actually has a nVidia GT 550m graphic card, but I wanted to test how well the HD 3000 can play games.
At 1366x768 resolution you should be able to play the game with a mix of low and medium settings. You'll need to experiment to determine what settings are best for you.