Yuck! Sorry to hear about your trouble.
The leak can be caused by several things, from a leaky hose (there are tons of them in there) to the reservoir to the radiator. If it is the seam, I don't believe it can be fixed.
The $875 price tag is about on par with most. It's an expensive part.
If you want to save some $$$, try Sunset Porsche for the radiator itself. It will probably be about 60% of the local dealer's cost. Then you can get the local specialist to put it in.
It seems to be a pretty easy DIY if you're game. There's a great write-up for adding a third radiator at
http://www.renntech.org/forums/index.php?act=diy&code=diy_rad You can use that to see what it takes to get to the radiator that needs to be replaced if you're interested.
Heck, to save some labor cost, fly me down there for $200 and I'll help you with it over the weekend of the 10th or it's $150 for the weekend of the 17th.
Hope it goes well!
