Only tested on XP, but not using wmi:

 Code:
ipconfig | findstr /c:"IP Address" > ip.txt
set /p ip=< ip.txt
for /f "tokens=2 delims=:" %a in ("%ip%") do set ipn=%a
for /f "tokens=* delims= " %a in ("%ipn%") do set ipnum=%a
for /f "tokens=1,2,3,4 delims=." %a in ("%ipnum%") do set ip1=%a&set ip2=%b&set ip3=%c&set ip4=%d