If you want to stick with fixed IP addresses, try the command line tool NetSh.
NetSh /? should give you a good indication what it can do, but I’ll give the first examples:

netsh interface ip set address name=”Local Area Connection” static 192.168.168.10 255.255.255.0 192.168.168.1 1
‘ Used to set the address to 192.168.168.10 with gateway 192.168.168.1

netsh interface ip set dns “Local Area Connection” static 192.168.200.200
‘ Set the 1st DNS server fixed to 192.168.200.200

netsh interface ip add dns “Local Area Connection” 192.168.200.201
‘ Set the secondary DNS server

netsh interface ip set wins “Local Area Connection” static 192.168.200.202
‘ Set the WINS server

Keep in mind that the command accesses your netwerk interface by name, so change the name “Local Area Connection” to whatever your network card is labeled.
You can easily put these NetSH commands in a batchfile, and thus create two batchfiles that do the trick (one for office settings, one for home settings).
Good luck!

My laptop use different IP at office, and need to change to other IP at home.

Googling for solutions land me here. I wonder how the others dealing with multiple IP.