The ancient pyramids are hard to see; you may need to hit the alt key to be able to grab the one that should be there. When the single teleporter stone was replaced in your inventory with an ancient pyramid, it may have been moved under something else.
A single skill point in Repair would be very handy.
If you just need enough to repair your current equipment so you can continue and get loot for future repairs, potions, etc. there is a way to get more gold. Drag a stack out of (or into) your inventory (or container) and hold down the control key before dropping. This will bring up the split stack pane; type in a negative number and hit enter (the checkmark will be greyed out). This can also be done in the trade window.
It is possible to get back to Rivellon to pick up items, but this probably will not help for completing quests;
Teleporting Anywhere, via hex editor
