I think two hours of walking is great! Congratulations on making that step toward a healthier you. However, it will not get you to your goal - I am not sure that anything will get you to the goal you have set. You'd have to drop 1.5 lbs PER DAY - eep! The only way to achieve that is to lose a limb!
However - You can keep up the walking, combine it with calorie restriction (or carb restriction or whatever other plan you would like to follow), and by the time school starts you can be well on your way to achieving your goal. Depending on your age and other factors, maybe you can be 10 or 15 lbs closer! Wouldn't that be great? A month from now, you will be glad you started today