Rename or insert Info into filename

New to this type of Tagging but so far I love the program. I have 2 questions simular in nature, but I was unable to find an answer searching the forum for the past 2 weeks.

Q #1: I have custom file info after "Title - " I want to keep
How do I rename the filename with changes, but without removing my custom info after "Title - "

I Have tried Tag - Filename EX: %artist% - %_filename%
But it gives me Artist - Artist - Title - My Custom Details.mp3

Org.: Artist - Title - My Custom Details.mp3
New: New Artist - New Title - My Custom Details

Q#2: Along the same lines except I want to insert say BPMs into the filename.

EX: Artist - Title - My Custom Details.mp3
to
Artist - Title (BPM123) - My Custom Details.mp3

Thanks in advance for your help.

Once you have all the additional data stored into separate tag fields, you can assemble the filename using the content from the tag fields in any order you like.

You can do this with Mp3tag in different ways. The "Convert" section provides the tools.

As far as the file has no standard tag fields set yet respectively existing tag fields are allowed to be overwritten, you can copy the text parts from the existing filename into their related standard tag fields, like TITLE, ARTIST, COMMENT and so on.
Additionally you are allowed to create your own user defined tag fields with names of your own inspiration, for example MY_INFO.

I suggest that you first split the existing filename by it's item parts into separate tag fields using the converter "Filename - Tag".
Then assemble the new filename using the converter "Tag - Filename".

DD.20100819.0815.CEST

Alright I'll give it a shot. Thanks for your help.

Update: That worked. What a fantastiic program.

How can I rename Artist:

 from                               to

Crystals, The > The Crystals
Hyland, Brian > Brian Hyland
Shadows, The > The Shadows
Vincent, Gene > Gene Vincent
Withers, Bill > Bill Withers
King, Ben E. > Ben E. King

Try:
Action Groups
Field: Artist
Regular Expression: ^(.+)\s(.+)$
Replace matches with: $2, $1