When the 30 day notice expires and she has not moved, you need to file and serve an unlawful detainer action against her. The owner is the plaintiff, not you and the safest way is to have the owner sign the paperwork and fax it back to you. Don't forget the verification.
Notice must be done properly. The complaint must adhere to the notice. You can lose these things very easily if you don't know what you're doing. You might seek legal counsel ;-)
You're not the ones with rights, it's your fiance's friend, and if the tenant doesn't move, then the friend either needs to file an unlawful detainer suit pro per, or hire a lawyer (assuming they're not incorporated or an LLC, in which case you could appear in court for the friend's company).
Please see the guide linked below, which has a step-by-step explanation of the procedure plus all the necessary forms.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.