Well i am very sorry to know about the ill health of you mom.Well if she has been operated by a onco surgeon and a proper staging surgery has been done followed by chemo, i am sorry to say that with this high titre of CA125 of 320, she may be having recurrences which are not clinically obvious now.You need to consult your oncologist
to try second line chemotherapy
after few investigations to search for the recurrences. If a proper staging surgery has not been done, you must consult a gynecologic oncologist.CA 125, is only a biological marker which shows about possible remission or recurrence of the disease status. You need to treat the primary disease to get the values low.
hope your mother does fine. take care