Close with this Query. Need help with last bit.

The query below gives me almost what I need.

SELECT u.id, u.email, m.first_name, m.last_name, i.date_worked
FROM users AS u
JOIN meta AS m ON u.id = m.users_id
LEFT JOIN items AS i ON i.users_id = u.id
WHERE (
i.users_id IS NULL
)
OR i.date_worked NOT
IN (

SELECT items.users_id
FROM items
WHERE items.date_worked > "2010-10-20")

Gives me:

1 admin@admin.com Admin istrator 2010-10-22
1 admin@admin.com Admin istrator 2010-10-09
1 admin@admin.com Admin istrator 2010-10-14
1 admin@admin.com Admin istrator 2010-10-14
1 admin@admin.com Admin istrator 2010-10-11
1 admin@admin.com Admin istrator 2010-10-19
1 admin@admin.com Admin istrator 2010-10-20
1 admin@admin.com Admin istrator 2010-10-18
1 admin@admin.com Admin istrator 2010-10-19
1 admin@admin.com Admin istrator 2010-10-22
1 admin@admin.com Admin istrator 2010-10-21
1 admin@admin.com Admin istrator 2010-10-21
1 admin@admin.com Admin istrator 2010-10-20
1 admin@admin.com Admin istrator 2010-10-13
1 admin@admin.com Admin istrator 2010-10-21
1 admin@admin.com Admin istrator 2010-10-10
1 admin@admin.com Admin istrator 2010-10-22
1 admin@admin.com Admin istrator 2010-10-22
1 admin@admin.com Admin istrator 2010-10-22
2 newuser@localhost.com Jane Tester NULL
3 jb@yahoo.com Jim Brown 2010-10-16
3 jb@yahoo.com Jim Brown 2010-10-20
3 jb@yahoo.com Jim Brown 2010-10-21
3 jb@yahoo.com Jim Brown 2010-10-21
4 tomtenor1@yahoo.com Tom Tenor NULL
5 johndoe1@yahoo.com John Doe 2010-10-19

What I want is to return just a unique userid and email address for any people that don't have an item submitted (the NULL entries) and don't have anything submitted beyond a certain date. So I would have one entry for the admin if they fit that criteria. Any help would be appreciated.