For rep[lacing the radio antenna, there is 2 options you have. Since you have an LE, You have a power antenna. To replace the mast, just get a new one, and unscrew the silver thing on top of the antenna base on the outside of the car. And get the antenna out. More to it then that, but let me know if you plan to do that.
2nd, you can do a Honda S2000 Antenna conversion for a nice custom look. Pretty easy to do and looks good. Also not too expensive.
Let me know if you want more info on either. :)
Adam