theme you bought (and every our other theme) is fully working, and all the parts you see on theme demo are packed in theme.zip file. You don’t need Photoshop to finish anything with this theme (I assume you’ve read docs about changing the logo, but theme you’ve bought doesn’t have logo/image, it uses plain text in site title). Even if it uses logo/image, there’s free alternative to Photoshop and it’s called Gimp which you can use to edit logo.psd that comes with our older themes.
If this is not the case, please describe what you mean by “not all the parts are available”, we’re here to help. Let us know!