Yes, ghee is basically clarified butter; it's okay to use regular cow's cream butter, and cook it longer until it is a darker gold (but don't let the solids burn).
Garam masala is a basic ground spice mix -- think of it as the "authentic" curry powder. There are a couple of recipe for garam masala here:
food.sify.com.
This is an online source for ingredients:
ethnicgrocer.com. Finally, here are two sites I like for glossaries and translations of Indian food terms:
cuisinecuisine.com and
daawat.com. The latter one is especially good because it gives translations from/into many of the major languages of India.