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
. The latter one is especially good because it gives translations from/into many of the major languages of India.