Welcome to the site! It sounds like you're off to a great start!
I agree with the previous poster that cutting down on the amount of processed food in your diet will help keep your sodium levels in check.
As far as calcium goes, here's an article with dairy-free calcium sources that should help: www.sparkpeople.com/resource/nutrition_art
The best sources of potassium include dried fruits, nuts, green leafy vegetables, mushrooms, bran, wheat germ, yams, bananas, and oranges. Good sources include many other fruits and vegetables as well as meats, fish, poultry, and legumes.
I would recommend updating your calories burned goal to reflect how much exercise you're doing each week. That may or may not change your recommended calorie range.
It's normal to lose more quickly in the beginning, but that should start to slow down as your body adjusts to the changes you're making.
Hope that helps,