Variables in macros

I'm writing a macro that would be much faster if I could store the image name, then pop that in at various points in the macro.  I'm using a mockup PSD we purchased for wallpaper patterns.  I'm rendering a file from a pattern image.  I've written the macro that copies the image, places it into a .psb, then places it into another .psb.  The hold up is at those points where a filename needs to be used, as in 'Save As."  If I had that name insert itself, then the macro would choose what file type, we could do a real batch.  At the moment, I'd be happy just to have the macro 'play' when I manually tell it to, file by file.  This issue is what's holding it back.

Or perhaps there's a whole other way of approaching this.

Thanks for any help.