Hey, call your doctors office. A lot of times doctors offices have an answering service (for when the office is closed)
the answering service can have your doctor (or another doctor that's on call) paged. You leave your name and number with the operator (at the answering service) and the doctor calls you back.

Usually they have no problem renewing your prescription.

Some offices don't have an answering service, so this may not help, but I thought you should give it a go!

I don't know if it's such a good idea for you to take your sisters pills... Not only will it leave her out of a pill, and in a jam at the end of her supply... But also, I don't know how transferable birth control pills are.

If your doctors office doesn't have an answering service... Call the hospital, and ask them about taking your sisters pills... I'm sure they will have an answer for you, and even if they don't there are plenty of docs around there that they can ask! : )

good luck!

~qriosity~