Money Owed as part of divorce settlement

My divorce was final on May 13, 1992 in the State of California. As part of the divorce settlement, my ex-husband was to buy-out my interest in family home in the sum of $12,340.00. The buy-out was to be within 2 years, or otherwise the home was to be sold and when sold I was to get $12,340.00 out of the net equity of the sale. He paid me 50.00 per month for two months and within the two year period, he lost the home due to non-payment of monthly note. In May of 2000, I went to see an attorney, who advised me that it would be worth my while to go after the monies owed me. He suggested I go through a collection agency. I have been working with a collection agency since June of 2000 and have gotten no where. They had promised over and over to resolve this by the end of Oct, then Nov, then Dec, then Jan. I need to know where I go for resolution?

Also, per divorce agreement, child support was to continue until my son was 19 if full time student and living at home. Child support stopped the month after my son, who is a full time student and living at home turned 18.