Thoughts:
1) Mileage is not 0.33 cents per mile. You should be paid at the IRS rate which is 57.5 cents per mile.
http://www.irs.gov/uac/Newsroom/New-Standard-Mileage-Rates-Now-Available;-Business-Rate-to-Rise-in-2015
2) you made the mistake in not bringing up the mileage. Don't "wait for her" to bring it up. You want to be paid? Bring it up.
3) She thought grandparents left you the cash. Maybe they forgot. So tell her you weren't paid. Then she pays you.
4) If you are actually driving over 200 miles per week for the job, which I'm not sure I believe, then you should have brought up the reimbursement MUCH sooner. You should not be including your commute time to and from work.
I don't even understand what you're asking. We don't know what your MB plans to discuss with you. If you want to be paid mileage, print out the above info if you need "proof" of what is legally required.
If she's paying you while the kids are in school, I don't think it's unreasonable to ask you to be available for things like pest control and cleaners. Cleaners come once a week at most, right? Pest control is once a month?