I can't answer your question about the broken antenna lead...ouch...

The factory radio is a "diversity" system...meaning that it has 2 antennas
(one on each side, hence the 2 antenna plugs), and the radio switches back
and forth depending on which one is getting a better signal.  Same
technology used in any good quality wireless PA microphone.  One of those
antenna plugs is standard size, the other is smaller than standard (and
obviously the one you won't use).

Are the antenna leads broken on both sides?  If not, and it's the one tied
to the normal sized plug, perhaps you could move the "normal" plug over to
the other wire...

If you haven't found out the hard way yet, there's also a particular wire in
the factory harness that you need to feed out 12v to in order to power the
antenna amplifier.  You won't get very good reception without it...  The
harness I bought didn't have that pin, I had to tap into the factory wiring
for just that one wire.

I did the work in my 2002...but sounds like 2001 is identical.

Wesley