Its really not that complicated. Paste the function to the bottom of your GPO script. Then you would have your GPO script to do things that require admin privs, and then at the end of the GPO script you would add the example lines to run another script using the function.

Something like.

 Code:
;GPO script
;...code
;...code
;
;Insert example code below
if instr(@producttype,"Vista") or instr(@producttype,"Windows 7")
  $RC=RunAsInteractiveUser(@scriptdir + "\kix32.exe", @scriptdir + "\mapdrives.kix")
  ? @serror
endif
;
;Paste Function at the bottom of the script
function RunAsInteractiveUser
;...
endfunction



How to use UDFs -
http://www.kixtart.org/forums/ubbthreads.php?ubb=showflat&Number=81943#Post81943