Forgot something..
GRAF:
If you want to get that third level orb, you can either sell one of your higher level items (Not just subtract the price), buy the item straight out, or just downgrade, but I won't be allowing you to divie the 'effective value' around. The three items you get have a MAXIMUM level of 5, 6, and 7. If you want to go with a lower level item instead, feel free, but you're not getting anything extra for it. (sorry)
Also, just to point out - There IS a lvl 6 orb in case you didn't notice it, Magic Orb +2 is lvl 6. If you'd rather go for the lvl 3 Orb of Inevitable Continuance +1, then go ahead. OR you could take the lvl 5 Orb of Sangiunary Repercussions +1.
As far as the rituals go, that's one of the things your extra money can be used for. You'll note that each ritual has a 'market price'. Page 300 of the PHB says this is the "cost to purchase a ritual book containing the ritual or copy a ritual into an existing ritual book. A scroll containing a ritual costs the same amount". If you want a ritual, go ahead and buy it, along with the components.