More information would be helpful. Does she have other retirement funds? A pension? Alimony? What age do you/she hope she can retire? Will she qualify for Social Security?
Yes to the self-employed retirement plan. Yes to index funds. Good job there. I suggest a 30% bond/70% stock split. Without more info, it sounds like she needs to work for another 15 years, so, in about 10 years, move to a 40/60 split, and when she retires, move to the 50/50 split.
I suggest a self-employed 401k and ROTH. Talk to a professional, but using Fidelity's calculator, it looks like she can put $22,300/yr in a SE401k and $6,500/yr in a ROTH. In 3.5 years, she'll have shoveled $100,000 into retirement accounts.
I'm not sure it makes sense to think of it as though she's living on the bank money, while banking her salary... but whatever works.