Fixing MySQL database

I tried to upgrade from 2.0.7 (the second-latest, I think that’s it?) to 2.1 yesterday, and basically what happened was the upgrading script told me the memory limit was too small or something of the sort, so I did a bit of research and then put a “ini_set(“memory_limit”,”12M”);” in the upgrade.php script. Then the MySQL wouldn’t complete properly, so like an idiot, I copied what I could from the upgrade-schema.php into phpMyAdmin, but of course didn’t realize it would only tell the database to create new tables, not put the new fields in. I am not sure how to get it to do that, what precisely should I do?

Of course, usually I’d just restore the old database, but like an idiot again, I also forgot to back up my database. Yes, I have learned my lesson.