Backing up?

My WP installation is on a Unix server farm called Prohosting.com. Very nice folks to work with, and I've been using them for over 10 years.

They do a tape backup every day, but they say it's just for real emergencies. I think they mean something catastrophic on their end, like a fire or tornado.

Up to now, our community newspaper site has been all done via Dreamweaver, regular HTML files, so my partner and I have each have the whole site on our home computers (we're a 2-person team with volunteer reporters in our town) as another backup. Now, with Wordpress, of course, we won't have the full site on our home computers anymore because it's in the database on the server. All we'll have will be the source emails and Word docs we use to create the WP posts.

The other day, I asked Prohosting to do a backup of the test WP files. They did, and then I got an email saying we'd gone over our disk storage quota. The "dump" had created a huge file. (NOTE: I do have 3 installations of Wordpress right now, to easily test various themes and options.) Obviously, that's not the thing to be doing.

What do you recommend? Do we even need to do some kind of backup other than the tape backup done by Prohosting every day?