Depending on what version of windows you have click on the windows logo or start button or whatever you have at the botton left of you screen. In the search box or by clicking on 'run' again depending on the version of windows type 'dxdiag' and hit enter.The second tab should show you exaclty what video card you have installed.
Gives the same card name but a few more details. Not sure if its relevant or not but here's the rest of the info.
Name: ATI Radeon HD 4300/4500 Series
Manufacturer: Advanced Micro Devices, Inc.
Chip Type: ATI display adapter (0x954F)
DAC Type: Internal DAC(400MHz)
Approx. Total Memory: 240 MB