As per your scale question, I would look at reviews on amazon, but I will say that you can make sure your scale stays accurate by keeping it only in one place and not moving it as well as making sure it's calibrated.
For an activity (as well as calorie) tracker, I use my fitness pal. It works for me and I like that I can see my activity and food in one place.
August 30 Goal: 169
September 31 Goal:160 January 31 Goal 145
August 31st Mini Goal 169