Cycles GPU rendering is currently in a beta stage, for all graphics cards. Your graphics card is known as an AMD graphics card, so you would need to enable OpenCL to use your GPU. Note that OpenCL rendering is very primitive, with no support for HDR textures, a potentially unresponsive window when rendering, lack of memory sharing (between individual graphics cards), and other issues. You would only be seeing a maximum of a 20% decrease in render times, with an average of about 10%. That is assuming your GPU can even handle your scene, so you might waste more time messing around to get things working that if you just rendered with your CPU.
However, feel free to attempt GPU rendering if you'd like. You will need to enable OpenCL rendering first, so [here](http://blender.stackexchange.com/questions/7485/enabling-gpu-rendering-for-cycles) is one article that may help you.