Allowing only certain MAC addresses or blocking specific ones would probably only stop this guy for awhile. It is pretty easy to capture MAC addresses and then spoof them.
Using this in combination with encryption would work better, although this also can be broken.
WEP is the older encryption method that has fewer compatibility problems, but is also much easier to break. There are readily available tools you can download to do this.
WPA personal is much more secure, but can also be broken.
I would recommend starting with WPA personal and if all the allowable computers don't have a problem, then stick with that. If some of your allowed users keep getting disconnected with WPA, then go to 128-bit WEP.
Here is a link to a document that describes how to configure the router for StarBand:
http://www.mobileinternetsatellite.com/Downloads/SBNetworkSetup.pdf