I just got a punching bag yesterday. I have a treadmill already and I walk/jog about 2miles a day. I was wondering if I should do the bag first then jog or jog first then hit the bag? Or does it even matter? Also I plan to get some weights this week. Should I cut down the walking or is it still ok to walk everyday and do weights everyother day.

Do punching bag first and jogging after. Your body uses glycogen for the punching bag and if you burn it all up doing cardio first, your energy for the bag will be less and you may lose some muscle.
You can walk or jog every day if you like. Just allow for a whole recovery day once in a while. When you get your weights, I'd recommend no more than 3 sessions per week of full body workouts to begin with. Eventually you may want to start working a split, but just remember that muscle growth occurs outside the gym, not during the workout.