With all respect, unless you're fluent in systems design, database administration, server- and client-side scripting, web design, and various markup languages, your best bet is to contact a professional. While simple page layout with static content is fairly easy (deceptively so when using programs like Frontpage or Dreamweaver), what you're discussing here is a full website with backend systems requirements, and that's not something a layman's going to have a whole lot of success with unless they've got a lot of time to ramp up on the technologies involved. As an example, user logins:
A properly implemented user login feature (which would be absolutely required in your example of a dating website) requires all of the following:
User input forms
Server-side scripting to do all of the following:
- sanitize any input from the user
- validate the user (ie. verify the username and password are correct)
- interact with the database during validation, user creation, password recovery, password resets, account deactivation, etc.
A database (yes you can get away with stashing data in XML files but that quickly gets ridiculous, especially in this instance)
And all of this is just to get your users account created and get them logged into the website, we haven't even gotten to user profiles, messaging, forums, etc.
My advice would be to do a quick search for web design firms in your local area and contact them for an estimate for a site overhaul. If they're too pricey you can also consider hiring a professional web developer and keeping them in-house to maintain/upgrade the site.
Good luck!