You can definitely customize the theme to suit your requirements, whether that's changing colors, layout or functionality. The theme is not encrypted, so you are free to make changes as you wish. If doing so, we recommend the use of a child theme so that you don't lose all of your modifications in the process of an update. Documentation relating to this can be found
here. There are some nice examples of modified JobRoller theme sites in the
AppThemes customer showcase.
AppThemes does not offer customization services, however we do have a
certified partners page where you can find developers for hire. If you make contact directly with an outline of your requirements, they will be able to provide a quote for the work. Thanks.