keyfob to computer

[vdvb]

hello everyone,
I am looking for a usb receiver that can intercept the 3 or 4 commands from a keyfob.
so that i can then program in my java program
if keyfob button A is pushed do something
if keyfob button B is pushed do something else
if keyfob button C is pushed do something else else
if keyfob button D is pushed do something else else else.

If would like to take a keyfob like this(encoded)
http://www.rf-data.com/productshow.asp?ID=148

i know there are also receivers on the site but not usb

if there are no ready made solutions is it hard to make one myself with one of those receivers?
if yes how?
keep in mind that I am a (handy) programmer not an electronics engineer.

Thx in advance