You may not need to replace it. Go to the following link:

http://au.geocities.com/ozbrick850/keyless_remote-rangeext.html

This link tells you how to put a decent antenna on the receiver. Also, there are discussion threads on ozbrick850 that indicate the receiver doesn't really often go bad, but is very sensitive to interference and has a very mickey mouse antenna....

Got mine on e-bay and even bought the reprogramming procedure. If I remember correctly, you toggle the key from the off position to position "II" 5 times. On the 5th time, you keep the key in the on position ("II") and push and hold either key on the remote, preferably the unlock key. That should be it but it took me several times to get the remote to program correctly. If you have 2 remotes to program, you have to do them both at the same time, program one then immediately the either within 30 seconds or so (i.e., push and hold the unlock button on the 1st remote, then release, then push and hold the unlock button on the 2nd remote within 30 seconds, then release. This should program both remotes.

Good Luck.

Keith