Combining Finder's File Open/save dialog with Alfred
Once you find the file using Alfred, you can copy its path to the clipboard and paste that path into the Go to Folder tool of open/save dialogs.

Find your file in Alfred, press the right arrow key to view the list of operations for that file, the up arrow key to go to the last option (Copy path to clipboard), and then the enter key to activate that option.
Switch back to the open/save dialog, press cmd-shift-g to  open the Go to Folder dialog, paste the path in, and hit enter. The file will be selected and you can hit Enter to open/save.



If you're interested in getting some more flexibility out of Open/Save dialogs, I highly recommend Default Folder X. It's immensely powerful and customizable and could eliminate the need for workarounds like this.
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