this is my problem -

I'm running a vBulletin powered board, with MySql (now running MySQL 5.0.67)
two years ago We've tried to convert our database using a script (vCharset Converter)

we've converted the DB, and got a utf database, we used to have latin1 Collation in our tables.

the problem was that the content inside the DB wasn't in Hebrew, it was a lot of gibberish, we've followed the manual, and the content is showing in Hebrew on the forum. (but it's gibberish in the DB)

Recently I've seen another forum's DB, coded to UTF8 to, but you could see Hebrew content inside the DB.
We have a few problem in the site because of the gibberish, there are places which show gibberish and some of the user names are in gibberish, basically there is a lot of mass.
I want to reverse what we did, or fix the gibberish problem (some how).
How do I do it? I'm using phpMyAdmin to explore the DB, I've searched the net and found out a lot of things about these kind of problems, I'm almost sure that the content of the DB wasn't effected by using the script, it was the charset mostly, I heard that there's a way to fix the problem with mysqldump or something similar, the DB weights 3 GB.

There is another method that says that I need to install MySql 3.x and export my db to a server using that version and the charset will be removed or something.

I really need to fix the problem and see the Hebrew content inside the DB too, I don't know which version of MySql we've used when we converted. I think is was 4.x.

some info - MySQL charset: UTF-8 Unicode (utf8)
MySQL connection collation: utf8_unicode_ci
219 table(s) Sum 6,253,964 MyISAM utf8_unicode_ci 3.3 GiB

even though we had gibberish inside the DB we kept on using utf8, and we had something like 700K of posts and 60K new users since then, so we can't lose it

Thanks a lot