How to change display information

Would like to change the information displayed in the ad.

Would like to end up with a Headline(Title) without the 'Title', no 'posted by' information, ad expiry date, or cost of ad. And then the description as is. I would also like to add new fields to display, like telephone number, website url and email address. (Maybe even make the email address clickable.)

Do I need to change the template files? If so, which files do I need to change? What about adding new information (like 'website url')?

Thank you!