I believe the "Comic-Con promo" you speak of was a small pamphlet that served as a preview of the first issue (or first chapter of the graphic novel) with some black/white pencil sketches.
I got my copy of the graphic novel for $10 new from a local Borders, but considering the current condition of Borders it may be difficult to get it from there.
Jokes aside, your best bet would be to check out the graphic novel sections of some local bookstores or get Tron: Betrayal comic book issues 1 and 2. The only difference between getting the two comics and the graphic novel is that the graphic novel has a prologue covering the events of the first TRON movie and an Epilogue that covers CLU's takeover of the grid and Flynn going into hiding.
The two comic issues can probably be found on several online retailers or (maybe) a local tabletop games or comic book store.abortion pills online abortion questions cytotec abortion