According to this GamesRadar Article the release date for the GameBoy Advance version of Grand Theft Auto has also been held back a week. It says 'late October' but one would assume it would have the same release date as San Andreas.
As for the top-down GBA version of Grand Theft Auto, which was also due to be released on 22 October, this is now scheduled for "late October" so we wouldn't be surprised for that to also be put back to 29 October to coincide with San Andreas.
Following the news of the release date of GTA Advance, Dale Massey has created some fake boxart for the game and it looks pretty good. He has even made a full version which you can print out and make the box for it.
Click the thumbnail to see it in full
If you would like the whole box which you can cut out, Click here to get it, its already at the exact size so just print it out and cut it out.
Gamespot and Nintendo have confirmed the release date of Grand Theft Auto Advance.
Coincidentally it has the same release date as San Andreas - October 19th, Rockstar seem to be keeping quiet about this one like they did for a while with San Andreas. We'll have more info on it as we get it.
Link: Nintendo's Fall Schedule @ Gamespot