thanks guys for the responses. i'm such a MIUI noob. i will try this now.
Edit: CRAP. i forgot i accidentally uninstalled the MIUI backup -_- i'm screwed now aren't i?
Nah, I don't even use it, there are many ways around it. Try MyBackup Pro for and/or Titanium Backup. You don't really need to back up your apps since they should automatically restore (it only takes me 10-15 minutes to get them all back on wifi). But you can use Titanium Backup to backup some app data (and also homescreen layouts if you do a backup for Launcher2).
I use MyBackup Pro to backup most everything else, including system settings. The only thing I usually have to do is re-tweak settings for MMS, Calendar, Browser, things like that.