Adding members without signup in mass?

I didn't really notice anything that showed this but that doesn't mean it is not possible so I thought I would ask the following.

Can you turn off the signup page and just have a login page only?
Can you choose to import or update your members using a external or by importing a database or .csv file for example?

The scenerio is we have a bunch of membership clubs under one site with different locations. Everyone signs up and gets approved at the meetings. They can't sign up from the website as they need to be approved by the board to be a member for that particular chapter. I would like them to be able to renew once they are a member if they choose using the online system.

We have 6 chapters and we are growing. We need something that we can use when we export our database into a .csv file that we can update the members on the site but also perhaps remove members who have not paid when we upload the .csv.

If this can work this would seal the deal. Or if you have another way to handle this operation I'm all ears for other suggestions.

thanks,
Jeremy

Okay, now that I know I can import via .csv that is great. Here it the next question about the import.

Can I use the import to take away users from the database? We use an excel sheet with all the users and other information on it. We also have a username and password columns. This just happens to be our current setup for login with the custom script we have. But what it does is rewrite the whole database for that chapter when it is uploaded. As that .csv contains all the relevant members and their information.

So if a member expires or we delete them from our upload .csv sheet will it erase them or there membership subscription from the site? We have to maintain this excel sheet and if we can use this sheet to do all the work on the site it would save us time. Or, can we put a certain column with the expiration date in it that Amember will use to auto expire them? Then if we happen to upload a new .csv again as we do every week if that person paid at the meeting instead of online then when we upload with the new corrected expiration Amember will also update the info in it's database for that member?

Thanks,
Jeremy