Completely lost. Help!
CiviCRM is open source software so there isn't so much a 'company' to go to for help as a 'community'. Within that community there are Partners who can provide professional support but they and many other users also provide a lot of free help through StackExchange (SE) and via chat.civicrm.org.

If it would help, we could have a quick skype call (~20 mins) just to help sort out some basics from you, and then via SE etc help you with your more specific issues.

You can ping me via peter.davis59 on skype if you have it, or I can supply an email if you do not.

Otherwise, to help you find what CMS you have (which may help folk help you) you could try to go to your /user or /wp-admin - the former would confirm it was Drupal CMS (the website that sits in front of CiviCRM), the latter would be WordPress. Or your site might be Joomla.

Going to eg /user would then help you 'request a new password' if there is already an account that was set up (hopefully you can access the email of the person who is no longer on staff). With that new login you should then be able to access the CMS and through that, find a link to CiviCRM for your site.