2002 Buick Century Antenna Replacement

We were going to replace the stereo with a JVC stereo we had. Anyhow, we were given some bad advice and we snipped off the end for the antenna cable on the understanding that you wire a new end on. Of course, now we know we could have just put on an adapter, but the damage has been done already. Is there any way to repair or wire on the new end, or do you have to replace the whole antenna? If you have to replace the whole antenna, where is it (there is nothing sticking up anywhere like a traditional antenna) and how would I go about doing this? Thanks!