How to change IP address using script on Windows?

I need fixed IP in three wireless networks I log in frequently.

It is a pain to set those IP and gateway everytime I change networks.

I am willing to write a script to change my IP and gateway between those 3 fixed IPs and a choice to make it get IP automatically (when I´m in another network).

A plus feature to my script would be if it could discover the wireless network I am logged in and decide the IP automatically.

Is it even possible?

Thanks.