I think what Lara means is that if you want medically sound advice, the best person to ask is a medical practitioner. Getting advice on the Internet is good and all, but to be really sure, your doctor should be the person you turn to ultimately since they are licensed and trained in that field, whereas people on the Internet are not. I'm sure you can just ring up your doctor's office and they will let you know the best way to take it.
As for the ratings, 1% means 1 in 100, so it's the same thing, just worded differently. Like I said, I also know women who have gotten pregnant on the pill, but they weren't taking it propperly and as diligently as you are supposed to, which causes it to be less effective, like any birth contol. For example, if you use a condom but don't put it on correctly, there's an increased chance you could get pregnant.