You can buy smaller heat sinks, search on newegg. I wouldn't start doing that sort of thing unless you know what you are doing, though a cheep 1950 is probably the best place to learn in case you break it
Is there another card inteh way, or something else? If it is a card perhaps you could movie it.
You have to make sure to consider things like space before you get a graphics card, though I can't imagine a 1950 cost you much to worry about that. Just buy a 4670 which is much smaller and roughly the same performance.