The only way to "fix" not being able to use the iPad because you don't know the password is to restore it in iTunes. Unfortunately.
Connect your iPad to the iTunes you normally use and, on the main Summary page, press the restore button. After iTunes restores the iPad (essentially, putting on a "fresh" iOS 6), you will be able to access the iPad.
If your most recent backup was made before the password problem, you can "restore using backup" and have all your stuff put back on it. However, if the backup was made after the password was set, don't use it as the password will be put back on the iPad and all your work will be for naught.
Good luck and let us know how you get on.
Marilyn