As others have advised, check the seat map a few times a day from now until Friday and maybe something will open up. You can also call the PM line and have them set your seat to be unassigned. Then, the computer will auto-assign something to you around T-24 and only put you back in the middle if it's the only seat position available.

It's always a good idea to check your seats after booking, especially with an automated site or a company travel agent in case they dump you in a middle or other seat you don't want.