DrCactus,
Check around local wreckers for a replacement top. Go on car-part.com and do a search on Boxster roof. I found a complete roof assembly with an aftermarket replacement canvas (I think it's GAHH) with glass window. Wrecker sold it to me for $500...
Just have to put it on now! That being said, my current top is in very good shape with a plastic window that was sewn in after the fact. If you can wait a few weeks, I would be willing to sell it to you once I get the new one on. Here's a pic of the old roof:
