I really want to switch from Viso to Axure but all my previous wireframes are created using visio. Is there any way to import these into Axure?

There isn't an import feature for Visio. You can copy and paste from Visio to Axure, but that creates a single image of the copied elements. Once you have the image though, you can overlay other widgets like the image map region to add annotations or interactions to parts of the image.