What are the tables I need to dump to be able to import them in a new installation?
I need this to avoid reinserting all the custom attributes for every new Magento installation.
To expand on Marius's comment above, the best solution would be an extension which contains setup scripts which insert each of these attributes.
n98-magerun.phar can be handy here.
n98-magerun.phar dev:module:create can create the basic module structure for you. Then you can use
n98-magerun.phar dev:setup:script:attribute to create setup scripts based on existing attributes. There may be some work required to add a setup resource to your module to make the setup scripts run and to test it all, which will require some programming expertise, but that's where I'd start.
You can find n98-magerun on github.