Oh yeah, I forgot to add, my MIL was sure my milk was either vinegar or water or both and kept on pestering me to have my milk tested. I rang around to try and find someone to test it and EVERY expert I spoke to said there is NOTHING wrong with my milk - they didn't even need to test it to know that. A lactation consultant told me that even women in developing countries, whose nutrition is below standard, have quality milk. You would have to be eating a Mars bar and Coke three times a day to have crappy milk.
I'm not too sure about how much rice cereal. Like Lindsey'sMom said, milk should be the primary source of nutrition at this stage. I think the brand I used to feed Luisa had a quantity guide on the back of the pack that said how much to give, but they are long gone!