I need to create a 'backdrop' against a model with photoshop elements. Help!?

Question

I used a real backdrop in about 50 photos I took of a model but the backdrop had all these little wrinkles in it; I tried blurring the backdrop, but it still looks bad. How can I extract the image of the model and put it in front of a layer that will simulate a grey backdrop without making it obvious that the image was manipulated, using photoshop elements 4 or higher? I did it once before but I forgot what I did. Help!