I bought Site Spinner recently, however I have not used it yet, just played a little with it. I very much doubt you can import whole pages into it.
I think you will need to select a template from within SS, then copy and paste text and images etc from your existing website to recreate each page. However I expect you will need to create the links and set the text formatting. So you would have a new site with essentially the same content.
I doubt any program would allow you to fully import web pages, retaining all the formatting and links. You may have a chance with an HTML editor, or perhaps Dreamweaver, but I expect you would still need to do some formatting, primarily because of CSS.
Depending on the size of your site, you could recreate your site quite quickly with Site Spinner, since you already have the layout you want, the text and image content. But for sure it will be a cut and paste job, of text passages and images etc independently.
Rick