Ok, to start with, OpenSuse 10.1 is an ok distro to start with, especially if you are new.
To install your radeon drivers, you will first need to install the kernel-source package. Start Yast (it should by in one of the system menus), and select Software Manager. When it comes up, select search, then type in kernel and run the search. Now, you will want to install the kernel-source package. It may ask to install several development packages, like gcc. Let it.
Once everything is installed, you can launch the ATI driver installation script. It will compile a driver specific to your kernel. From there, I think there is an aticonfig script that you need to run to configure Xwindows, but you might also be able to do it now in yast (I can't remember this step). The documentation for the ATI driver should give some guidence from here.
Now, as to realplayer and winamp, you have some options. Realplayer is available for Linux, just download and install it from real.com. Winamp is a different story. It is a Windows only app, but there are plenty of alternatives. The closest is xmms. It has the same look and feel as winamp, plus it can use winamp skins (and I think they are working on winamp plugin support as well). Other choices include Amarok and Banshee. Both have excellent frontends, and even will download coverart from the internet based in the id3 tags in your mp3/ogg files.
Good luck, and welcome to the community.