Don't give up that easy!
How many users do you have, and how much content? It might be easier to target certain areas that you want to save, IE member profiles, and have them rebuild/reload content that is less of a pain in the rear (photos, videos, etc). That's worse case scenario though.
Backup all of your content locally, as mentioned above you'll need to make sure you grab all content from your modules folders (photos are stored within modules/boonex/photos/files). Take a full backup of your database using phpmyadmin (don't rely on D7's built in backup, it's horrible). I like to create a backup of the core D7 tables, then separate backups of all the module tables but it can be tough identifying what is what if you are new to it.
Stand up your new dolphin site with a new database and load up the same modules that you had before. This is where I like to restore the core database tables, then one by one go through the module tables and files until it's all back to what I want.
If you want to keep it simple and just retain your members, backup the 'Profiles' table within the database and restore just that. You'll at least retain your member base, but they will be missing everything else.