A Couple Questions about Double Double

Hello, I just installed and configured Gallery 2 at www.catclubsf.com/gallery, but I've got a couple questions/issues.

1. How do I make it so that people can register an account to add albums and photos? I'm using Carbon theme, and I don't see a register button on the home page, only a login button.
2. What file do I modify to change the text that reads "This is the main page of your Gallery" on the gallery home page.

Thanks,
ax