I've seen them on eBay,
Easy fix, you'll have to open remote, remove ( goo ) silicone from antenna lead to receiver ( tan colored goo ) then once goo is removed, simply unplug lead, and plug in new antenna, I'd place some more silicone on the new connection to keep from coming loose! Reassemble remote ( careful DO NOT PINCH ANTENNA WIRE, while reassembling remote! )
Hope this helps!
J Dot