Well I think it's now knackered!
No point in trying to contact the manufacturer as Ultimate ceased to trade more than 20 years ago!!
The P.U coating as delaminated in the wash so you're effectively left with a Nylon flysheet that is at least 20 years old with no proofing.
Sadly I would say you've had your money's worth now and it's time to re-invest. If you're looking for a more modern aleternative to the Peapod consider Hillebergs Nallo range, the Lightwave Trek range, Macpac Minaret etc... All of these will be stronger and lighter than your Peapod.
You can save the tent materials for use as spares and repairs to other bits and pieces or perhaps you will be lucky to find a flysheet.