Okay...you confused me because you are using the wrong terminology and have your facts wrong so I am afraid i didn't quite get what you were talking about.
It now sounds as though you were on a fiancee visa, (rather than a spousal visa) and are about to marry. You then need to switch to a spousal visa, which comes with the right to work (NOT a 'work permit', which is something entirely different).
Anyway, you won't be able to change your passport in 18 days, so forget that. You are going to have to do as MeShell quite rightly says, and just travel under your maiden name. Even if you put your married name on the FLR (M) the visa will be issued under the name on the passport.
And they will let you travel on that, even if you use your married name in every other walk of life. Just because you marry, you don't 'lose' your previous surname.
Victoria