Should I add champagne/wine yeast to the secondary of this Export Stout?

it sounds to me you used too much extract to start with an og so high, obviously leaving it in the primary for 4 weeks has done no good whatsover....why did you do that?.....firstly rack it into something airtight with an air lock...you never know the racking may start it up a little........but i dont believe it will get down to the gravity you are looking for..........if i was you i would rack it, top it up, leave it for a week and taste it.....if it is sweet, well you know the starting og was too high so you wont do that again....if it is sweet.......putting a champagne yeast wont work, you dont have enough sugar...i would suggest you accept the mistake and adjust the original og next time....good luck