you might have a problem getting a job as a Spanish/English interpreter in China 

Questions:

are you looking for a job there? if so look on the jobs part of the site here.

have you asked her is she knows of any suitable jobs?

do you have a TEFL and can teach english, because most of the jobs available to foreigners are as teachers?

Have you looked into your GF moving to Canada?

I suspect you have but have decided it can't be done easily.

If you have loads of money and don't need to work you can apply for a S visa.  If You don't have a lot of money and need to work you need a Z visa.  As sorrel says above, your best bet to get a Z visa is to be a teacher.

Whatever you do, don't fall into the trap of working on a tourist visa.

There is lots of info out there on how do do it.

Good luck 

to be a teacher is better.