There's some mods out available for helping low end cards. Some of them just tweak settings, others might do things like turn off or simplify spell effects, however I saw one that was specifically for using higher settings on low end cards.
I'd reccomend searching the Mod Forum at
www.elderscrolls.com or trying
www.tessource.com maybe.
I might be wrong on the tessource url.
I had a low end card and ended up upgrading ;(