Enabling static IP is done using the router setup, just go into the router setup and enable it individually for each wireless connection.
It's not the laptop itself that has any settings changed, so when it connects to another wireless access point, it will be assigned an IP according to the settings of the router it connects to.
The IP is a local one, not to be confused with the IP assigned by the ISP, and usually has numbers like 192.168.1.64,65....upwards.
You will probably have to to the same for the repeater.
Does that help?