SQL Question

[Wir3tap]

Ok, our vbulletin site recently got hacked, we have pretty much moved everything onto our new site. (New Forum and Database, Same Cpanel.)

Here is the tricky question.

Our Old Forum, the database is still fine and had the old userid's. When we imported into our new forum our userid's got completely changed. This messed up our awarded medals. We imported the awarded medals table but they are still linked to the old forums userid.

How can I make a sql query to do this?

Heres the info:
New Forum: _forumsv2
Old Forum: _tourny

Tables in Old Forum _tourny:
users - userid, and username are the 2 fields. (Only reason bringing into user id and name is to match up something for the new forum.)

Tables in New Forum _forumsv2:
users - userid, and username (Userid to get the new medals to use THIS ID instead of the Old userid in old forums. And Username which is the common connection between the 2.
award_user - userid (This still has the old user id's in and needs to be updated to reflect the new user id's. This is the only important field in this table.)

Please help!

Thanks!