new to autoit, need help selecting radio button

I’m very new to AutoIt and I need help clicking a radio button in Windows.
 
Basically i'm going to create script (compiled to an exe) to do some stuff on first logon for new users.
 
I want to open the performance settings and click the adjust for best performance radio button.
 
I managed to put together the following bit of code to open the dialog box (first 3 lines are needed for something like XP, the last run last will open it directly if I’m running vista or later which is the preferred method apparently). I can’t figure out how to click the adjust for best performance and then click the OK button to dismiss the dialog box (2 Oks needed for win xp, only 1 for the others). Can anyone help? (There might be more than just English involved so I don’t know if trying to find that radio button by name or position is best)

In the code below, i don't even fully understand how the control click line is able to call up the correct dialog box. when i test on 2K8R2 for example, it works but I'm not even sure how it's clicking the right thing.

#include <GUITreeView.au3>

If @OSVersion = 'WIN_XP' Then
   Run('control sysdm.cpl,,3')
   WinWaitActive('System Properties')
   ControlClick('System Properties', '', 'Button2')
Else
   Run('SystemPropertiesPerformance.exe')
   WinWaitActive('Performance Options')
EndIf

Thanks