If you're responsible for caring for your disabled son from the marriage then you will likely be entitled to a higher amount to take that into account. Check out these LawAnswers Family Law Forum posts that touch on property settlement:
There are a number of factors that are considered in a property settlement and maintenance (see the Family Law Courts "Maintenance" page, "Property and Money Matters" page and"Financial cases" page). Remember applications for spouse maintenance (if you are a party to a marriage) must be made within 12 months of your divorce becoming final. A family lawyer would be able to give you personalised advice based on your specific situation.