Without returning to Rivellon, there is no way to retrieve your dragon or silver armour. If you have not completed the holy item quest (sacrificing two to gain one usable item), then they would not do you any good in the wastelands anyway. If you were going to go for the holy sword, there is a sword of the gods in a house which is potentially more powerful.
There is a way to replace quest items, or charms / statuettes (anything without random stats), but if done with equipment, the stats will morph.
Lost Items - guide and directory of inventory files 
