There are other ways for her to stay in Canada - however being sponsored as a married partner is probably your best option if you're ready to get married.
If you apply Inland, she could qualify for a work permit after Stage 1 (sponsor approval) which is 6-7 months. It's not recommended she leave Canada for any reason during the sponsorship. She would need to include the application for an Open Work Permit (OWP) and pay the fee for the OWP with her Permanent Resident (PR) fees.
She can also try to get a work permit on her own. She would need to find an employer that would give her a LMO.... but this is very difficult to get unless she fits into certain jobs that have needs for foreign workers. (Nanny and food counter attendant are the only two I know of and there are thousands of applicants for even one job.) So that's a way to get to work.
Depending on her Visa Office (VO), applying Outland might be as fast. Some VOs regularly finish in 7-8 months and she would have the ability to travel outside Canada - although she cannot be guaranteed re-entry. Once she's finished and has her PR, she can work anywhere she wants without needing any type of work permit, of course
If you're wanting to sponsor her, I would suggest to start collecting materials for the application
now. The police check in particular seems to take the longest, sometimes months for some applicants.
Make sure you read the sponsor agreement carefully so you know what you're committing to!
Most places no longer do court houses wedding - just an FYI. You have to contact an indepenant marriage comissioner to perform the ceremony. Some offer to do it at their home or let you pick a place. For example, we got married at a friend's house (she offered to host as her gift). Just make sure to check the legal requirements of your province before you go - so you have all the correct documents. And I'm paranoid, so I always recommend taking extra ID if you have it...
