Failed the Fuel Selector Valve AD during Annual

My annual inspection started out great this month with no engine issues and minor airframe issues - no surprises, just finally addressing nagging issues. Then it came time to conduct the dreaded AD 77-12-01. According to the AD, the maximum allowable fuel collected when draining the fuel selector in the OFF position is 0.5 ounce (one tablespoon). My fuel selector drained about 1/2 cup. My IA removed the fuel selector valve and attempted to clean the ball, seat, and replace the seals. After doing so two times, the leakage is still in excess of the allowable limits per the AD. This is a huge blow to my endeavors to stay in general aviation after 18 years and being a Cherokee 235 owner for 12 years. I must say that this is becoming the straw that will break the camel's back. Now I am not one to give up easily, but I am at the point here where I have nowhere to turn. My IA's suggestion is to find a used valve, but as we all know, our fuel selector valves are extremely hard to come by.

I am at a point of desperation here and need any help I can get. I don't want this to discourage me and lead to rash decisions like selling this great aircraft, but I am at my wits end with this next major issue. My research has led me to believe there is no easy or relatively inexpensive solution. Therefore I am coming to this great group asking.... no.... pleading for any suggestions anyone out there may have. I simply cannot afford paying thousands of dollars, especially for something as simple as this. The Mighty 235 sits with the annual complete minus this disastrous issue. Any suggestions would be greatly appreciated.

Thank you so much!