The DRI for protein (formerly the RDA) is 0.8g/kg. This translates to 0.36g/lb. So, at 156lb you should be getting 57g/day, not 156g/d. This amount of protein is easy to get through a vegan diet, as long as the diet is balanced with food from the 4 food groups... by that I mean Fruits, Vegetables, Breads and Cereals, and Legumes. Check out the site and if you have any specific questions feel free to post them!
There are many different ideas floating around about weight loss, fat loss, and getting in shape. Personally, I think that everyone is a little bit different, so always use any advice with a grain of salt, and check to see how your body responds.
To lose weight is easy, just take in fewer calories than you burn. To lose fat
is harder: eat a balanced diet, and get a mix of aerobic exercise (this will help burn fat while exercising) and weight training (this will burn fat during the muscle building/recovery phase). As I said, check out the other threads, and if you have any specific questions, feel free to ask.