I had a sex with my girlfriend a week before her periods but the condom broke when I was on her. Its almost one month now what should we do to avoid pregnancy?

Your question isn't clear. Your title says 'abortion' so does that mean she is indeed pregnant?
If you want to know about better birth control than condoms, the answer is the pill, patch, IUD, or tubal ligation, all 4 of which require a doctor to get. But they are the only ones that have a good chance of preventing pregnancy.
If you want to prevent that pregnancy, it's too late now. If you want an abortion, you need to find a clinic near you.

Please don't do an abortion, think of other options
There is people that would love to have children and just adopt one. If your young , I understand your stressed and can't support a baby at the moment but someone else might be able too. Hope this helps :) God bless you.