there are two ways to do it that I can think of.
1) Have the two tiles loaded into the tilememory when the tilemap is loaded (Just include it in your tileset) and then search for a specific tile in your tilemap, and then change the tilemap value to point to the nth frame of the tile in your tileset with an asm routine.
2) Have an asm routine executed every x seconds that copies the nth tile into the tile memory.
To find the tilemap offset look for a program called WRAPRE.
To find the town data offset, look in r&d or tutorials for `Yet another asm tutorial` [by Knizz]. The offset for that is in there. The values are just index values for a table of town names [there are 0x55 of them (which is one less than 0x5C)]
I would give you the offsets, but I'm away from my computer with that info.