gameboy color frankly, is close to extinct. I only have up til Game Boy Advance. and that's it. You can try ebay. but that's it. i can try looking around the states and singapore. but let me know what titles you need. will do my very best.

and yeah, expect it to be extremely pricey.

in the event where there are no more games for the GBC anymore, you can wait for the 3DS. It is to bring back all the older games from the Game Boy era also. Hopefully there's some from GBA too. Cuz that is getting more extinct too.