Apache 2 OpenSSL creation, configuration, Microsoft Active Directory Certificate Services

I have an apache2 webserver with openssl. This server is running WordPress Multisite. We changed the main network site domain, and need to create a new SSL certificate as we are getting SSL certificate errors now. This needs to be wildcard compatible for our various subdomains that the subsite WordPress MultiSite blogs use. Currently the /etc/apache2/sites-enabled/[login to view URL] file links to SSLCertificateFile that ends in .pem, I believe this is a linked hash, and would like to create a new one for the new certificate and key. You will need to guide me on the changes I need to make to get this configured, I can't provide remote access. I need to know in your bid how long this will take.