I broke it - can't see users anymore

I installed RT3 a few weeks ago, but now I’ve broken it: here’s what I did:

I thought I had it installed correctly, but as it turns out I had screwed up
the MySQL installation, and was actually running on an SQL database out of my
home directory. Doh! I restarted my machine after a power failure, and
nothing worked, which is when I discovered this. So, being an SQL newbie, I
dug around for a bit trying to figure out how to get my data back. I ended up
copying the “data” directory from my home directory’s SQL into the real
installation, messing with the permissions to get it working properly, etc.
Finally, I was able to run RT, log in, see my databases, etc. Great, I
thought. But no: as it turns out, even though I can log in properly, both as
myself and as root, the users list is messed up. When I try to show a list of
all users, nothing shows up, adn I can’t assign a ticket to anyone (including
myself). I looked in SQL and the users I want to see are there and are listed
as members of the Privileged group, but that’s about as far as my SQL
knowledge will take me.

Any suggestions of how to remedy this situation without losing the last few
weeks of tickets and user information?