My first recommendation is you need to work smart before you work hard. Be sure to have proper technique and proper form when completing exercise. Without these components, you put yourself at a higher risk for injury which will prolong your benefits.
In order to lose weight, you need to burn 3,500 calories which is equal to 1 pound of fat. In order to lose that weight, you need to know how many calories your body burns while at rest. Following, you will be able gage how much exercise is needed to burn those 3,500 calories. If you are unsure how many calories you burn during exercise then consider investing money into a device such as a bodybugg. A bodybugg will help monitor the calories your body burns during exercise. Again, after figuring out the amount of calories your body burns while at rest and the amount of calories you burn during exercise, you can effectively figure out how much exercise is needed to lose weight. Best of luck!