Yes - you can marry your girlfriend back home after you have become a permanent resident. You will have to sponsor her in order for her to become a permanent resident too and be able to move to Canada. Since you will be a PR, you will have to be living in Canada when you submit the application to sponsor her and will have to continue living in Canada while her application is being processed. Whether she will be able to join you as a visitor in Canada while you wait for her application to be processed depends on where she is from, if she needs a visitor visa to come to Canada and if that visa will be approved.
As for other options, you will have to provide a lot more background information about yourself in order for us to answer that (e.g. how have you applied for PR, where your girlfriend is from, etc.).
If you have further questions I would recommend you post them to the Family Sponsorship section of the forum.
And make sure that none of the information you give CIC makes them question whether you and your girlfriend might have lived together long enough to be common-law.
