Weight Loss

Hi everyone, I need some serious opinions.. 

Ok so I have been pretty much overweight all my life and now up to the point where i think is becoming unhealthy (aside from not looking great too). I have tried numerous diet and all have seemed to failed, not to mention the hundreds of dollars I have wasted on diet programs. So far I've tried: lite n easy, jenny craig, atkins diet, taking weight loss pills, etc... (It will go on for hours if I keep listing them up here). At times I'm really unmotivated and just can't be bothered anymore but I know that deep down I really have to do something about it. 

So now I've really come down to two things, healthy/balance eating plans and exercising!  Because I know there are no easy shortcuts to permanent weight loss. I've had some advice on starting off with cardio. Everytime I'm on a treadmill after 10mins, I get really bored and essentially lost all focus to why I'm doing in the first place then I give up and I just don't go again tomorrow. 
Or sometimes I go for a jog or something and then I'm really tired, like huffing and puffing like anything and all I want to do is just to get off the machine and lay down. I really want to run for like 30 mins straight!!  how do I do this??

HELP!