Paul,
Check you legal rights where you live. The seller is usually required to disclose this information. This is the same as disclosing information regarding mechanical problems with the property such as a gas leak or mold, etc..etc...
You may be well with in your rights to go back upon the seller to recoupe your lossm and I would definitely do so. There are more then likely annual fees that should be escrowed. My HOA dues are $250/ yr, but if you live in California I'm sure yours are much much higher then that. This is a REQUIRED expense to purchase the home, and much like homeowners insurance, must be disclosed.
My HOA is behind the eightball. The let people put up metal sheds and unapproved fences and swings and then to go back and tell the owner that they have to have them removed. It's much easier to put a copy of the HOA covenants on the door for the new homeowner to read. I actually have started a website for my subdivsion to enjoy, forums, forms, news, etc.
Have you received a copy of your covenants? Here's a copy of mine http://www.avontrails.com/files/covenants.pdf
Good luck.
Mike