Oh, okay. I read your previous posts. Truly, the main problem is not a lack of sex life. Diminished sex life is usually a symptom of other problems in a relationship.
You are dealing with a lot of issues here:
1. Abuse. Listen, if her father molested his granddaughter, you can bet that he molested his daughter (your wife) as well. I have experience here that shows many adult women have been abused by their fathers but they repress it. They live with that knowledge but it surfaces in other ways (namely sexual dysfunction later in life.) I know, on a personal level, several women who seem to have had a perfect childhood with continuing "normal" family relationships with the men who abused them horribly for years.
2. Emotional problems. Depression definitely shuts down a woman's libido. Men use sex as a way to boost their seratonin levels and feel better. Women can't get to the point where they want to have sex at all.
3. Financial struggles. The very problem that breaks up most marriages will put a huge damper on her urge for sex. She may or may not blame you or harbor resentful feelings.
4. Empty nest. Her mothering role has changed drastically and it takes time to adjust.
5. Menopause. This alone doesn't end sexual desire, but the changing hormone levels do affect her moods.
Before you can expect a better sex life, you have to deal with the unstable emotional/hormonal/chemical balances within both of you. There are counselors who offer services free or on a sliding scale as well a pharmacies who provide meds (I saw that Kristen already posted the link for the one recommended by Dr. Phil.)
Things you can do right away to help:
1. Stop asking for sex for now.
2. Exercise. Both of you need to exercise (after getting your doctor's ok) in order to pump endorphins through your body and brain. It's a natural depression/anxiety remedy. I can't stress this enough. If there is one panacea, it is exercise! You may not need medication, if you exercise regularly and hard enough to increase your heart rate.
3. Eat healthful foods. Eliminate caffeine (reduce the anxiety), alcohol or nicotine. Drink plenty of water. Dehydration causes a lot of surprising emotional problems.
4. Show affection and touch without the demand for sex. She will reject touches at first because she expects you'll demand sex afterward. Hug her a lot.
5. Work on yourself. Just as depression is contagious, so is happiness and joy. Exercise, try to focus on what is going well in your life. Work to improve your finances in a positive and hopeful way.
6. Send her to a doctor for a check up about the menopause symptoms as well as the depression.
I know you need sex and that sex would solve a lot of problems for you. But a woman doesn't work that way and it sounds like she has a lot to work through. If you can't afford couples counseling, send her alone. It sounds like she has to work through some sexual abuse issues which will definitely affect your sex life. It will take time and patience which, fortunately, it seems you have.

Many men share your exact--and I mean exact--situation. They are patiently working with counselors to help their wives. Their wives are very fortunate.
We're here to listen and help when we can. Let me know what you think of the suggestions and if they will or will not work for you.