Get Help from Bob Vila
- Give-Aways & Offers
- Monthly Must Do's
- DIY Project Ideas
- Step-by-Step Guides
- Inspirational Photo Galleries
But the answer to your question is that you have to increase the width of the rough openeing to accomodate the door and that is going to force you to also remove and replace the header above the door.
If this is on a bearing wall you will need a professional to make the adjustments for you.