Best way to do authentication?

I've designed and built my database containing all user info and such. Should I use ASP.NET Web Site Administration toolkit(login, user database) which would then give me two separate databases that I would have to use when updating user info??? OR should I create my own authentication just using my one database??? If the latter is desired, can someone point me to the right resources in learning authentication and webpage-to-user association???

This is bugging me because I'm thinking I should have set up the administration stuff first, THEN added all my other tables to that database...