Integrate a back-office database that can be browsed and edited

Dear all,

Me and a small group of friends are since some years running a successful but small conference. Typically we manage 20-35 speakers, 150 guests and 5 or so sponsors.

I would like to integrate a back-office section on the same domain so that we can run the whole thing from our site.

Specifically we would like our guests to sign up using a form on the site. These forms will then build our guest database, This database is simple and contains  only 10 or so datapoints (name, email, location, employer, job speciality, invoiced/paid and so on. We have the form page and it exports to 

We would like to be able to access and view this database from the SS site via a 'back-office' login link. From there we want to be able to browse this database for completeness and update tags (ie invited-->invoiced-->paid etc,).

This would obviously have to be password protected.

Can someone point me in the right direction?