If you right click on th desktop and go to "Properties" and then select "Settings" and then press the "Advanced" button, you will be taken to the ATI control panel , which allows a lot of different configurations (anti-aliasing (AA), anistrophic filtering (AF) and so on).
There is a slider which allows you to set Performance versus Quality which sets a lot of things for you. For AH, I would suggest setting the video resolution to either 1280x1024 or 1600x1200 and run with 4XAA or 2XAA, respectively.
Always use 32 bit color with this card.
You will also find the ATI driver version in this panel as well.
The AGP aperature size is located in the system BIOS. It should be set to either 64MB, or 128MB. Make sure Fast-Writes are off in the system BIOS as well.