Lemon grass is stalk (with a root). It is available in most chinese grocery stores or health food stores.
Kafir lime leaves will be available in a Thai/cambodian/vietnamese grocery store. There is no real substitute for them. I have tried lemon peel/zest etc.. but nothing comes close to the leaves.
Thanks Mograkali. I have the feelings I won't find kaffir leaves anywhere Its very hard to find Thai grocery store here..maybe in china town.
Now that I think of it..I. have seen kaffir leaves in thai curries and it smells really good.
Yes the kaffir lime leaves really add to the authentic flavour of thai food. Yummm! Lemon grass is also used to make kehwa tea and has a lovely soft lemony flavour.