Display properties by price

Hi. We use the Real Estate theme for our estate agency. I would like to modify the display options offered to users. Right now the site allows users sort properties by title, date, popularity, featured, rating, nearest. Don’t really care about popularity or featured and we don’t use rating so these options could be eliminated. Most importantly I want users to have the option to display the properties by price. How do I do this? I recall someone else asking this question recently but cannot find the post in the forum.

Thanks in advance.
Laura
http://www.granalacantproperties.com