Framerates not up to expectations

[AspiringFailure]

Now, it's not a severe problem.
My setup is:

Core 2 Duo @ 2.00 GHZ
2 GB RAM
ATI Radeon Mobility x2300

On low (With medium textures) I can barely get away with a framerate of 12 - 18 FPS. This is playable, but not wholly enjoyable or immersion, and even worse that's at 640x480 resolution. I do NOT have the latest "legacy" drivers from AMD's website, because for some reason they don't support the x2300 (Which for those of you wondering is basically an x1350)

I do have the latest drivers from HP but I doubt they're as up to date as AMD's legacy drivers. My main question is if such unplayable framerate is typical of my setup? Has anybody else with an x1350 or x2300 tried this game? I read in another thread one of the creators of the game running it with a much lower-end setup than mine, so I can't help but feel like I should at least be able to hit 30 FPS. I also dislike how the textures look on anything other than "high", but that brings the game to a downright crawl. xD I am playing with SSAO disable, bloom and all the motion blur effects disabled, parallax disabled, and shadows on low res and quality btw.

My version of Amnesia is the one included with the Humble Indie Bundle so if there's a patch I'm missing that is known to help, let me know. (I do have HORRID Internet though, so... if it's not going to help I probably can't bear to wait it out ^_^ )