Good day,
These two features will require advanced customization to implement as explained below;
1. You can try tweaking the existing separate login options for the job lister and job poster to your setup but would still require some serious coding work specially on additional user roles.
2. Likewise, there is no admin option for this yet and so will require code customization. The theme is not encrypted and so it can definitely be modified according your additional requirements. If you are not comfortable with codes, you can just hire a coder to assist you on its implementation. Appthemes also have certified community partners
http://www.appthemes.com/partners/ that you can contact for customization jobs.
Also, these features may already have been requested at the ideas exchange page
http://ideas.appthemes.com/jobroller/?orderby=votes of which implementation depends on the number of users voting for it.
Cheers,