Well, you have kind of an antique, Geoffrey. Or a classic. It depends on whether you are a glass-half-full or glass-half-empty kind of guy. Moonstone croaked a few years back. Which is too bad. It was a venerable brand that added a lot to the outdoor industry. I still have a few Moonstone pieces. A down sweater, for instance. And somewhere a bivy bag such as yours.
The bivy bag of yours is an interesting case. My recollection is that the thing weighs between three and four pounds, yet still is not much more than a nylon tube that one person slides into, and then gets stuck. No reading, no dressing, nothing. Bleh. That's why I never liked bivy bags. Theyre for emergency use, not camping.
Besides, you'll spend hundreds getting custom rods made. Just not worth it.
Moreover, these days, thanks to better designs and materials, decent little tents often weigh less than older bivy bags. REI's Quarter Dome T1 ($199) weighs less than three pounds yet gives you a shelter thats a little housenot a sort of, well, coffin. Yet its still very weather-proof. Criminy, you can get a TWO-person tent, Big Agnes' Seedhouse SL 2 ($320), that still weighs about the same as your bivy bag.
So there you go. Ditch the bivy bag. Buy a light tent.