This may seem a bit odd, but the willpower, drive, resolve... whatever you want to call it will come with the illness. I think b23 will find this out or agree as well.
When you think you are healthy, stopping smoking, losing weight, exercising, quitting bad unhealthy habits is really hard. You know that. When 'staying alive' becomes your top priority, all those things become very easy because you are motivated... REALLY motivated!! Your willpower, etc. will appear naturally as if by magic. It WILL appear.