Well, if it's like MY garden, all the weed seeds are sitting on the top couple inches of soil... if you turn them under, you are doing them a wonderful favor. :o) I'd remove it... really.... hard work now, but save you more later.

Smothering is another, much easier method, if you can get ahold of enough material.
The best thing to use, but kinda pricey, is straw bales. Cover the whole area solid with bales. Hay is ok also, because the whole bales will heat up and kill most of the grass seed. Both do an outstanding job of rotting out the sod by spring, plus the rotten bales will make a fantastic compost pile.

Cheaper, or free options are: cardboard - as many layers as possible, or newspapaers, weighted down with rocks or etc; landscape planting fabric - if you buy good quality stuff you can re-use this for some years; old cotton futons are excellent, or organic-fiber rugs. Whatever you use, it's best if it lets moisture through, as do all the things I've described. If you use plastic, it starves the ground of moisture and kill the worms and bugs and the things that break down the sod.

Thanks for the responses.

I just spent a few hours digging and I'm removing the weeds and grass. I did read about the newspaper method but I have so many rocks I want to start digging them out now so I'll be ready in the spring. I'll add manure and hopefully compost now also.

Thanks

Be sure to save and compost the plant material and associated soil that you are removing. It adds up to quite a bit of bio-mass.