For random loot, my first game I got a ring from one of the orcs outside Aleroth with a Repair bonus on it. I had one ring before then, but don't recall exactly when I got it; it was more likely random loot than purchased from George, though. I wore the ring with a repair bonus briefly, but found or bought another ring not too long after that (I kept any jewellery I found with Repair bonuses to use when batch repairing stuff to sell, as well as items with Identify, Trader's Tongue, Pickpocket, etc).
The first merchants that would have a good chance of carrying jewellery would be in Ars Magicana, far to the east of the farmlands after you finish in Aleroth. There are another couple merchants in Verdistis you can check (when you get there), though they would not have nearly the selection of the mage in Ars Magicana. Before then you will meet a travelling merchant on the path to the cursed abbey (north after you cross the bridge south of Aleroth) who has decent goods for relatively early in the game (don't recall if he has much jewellery), but you only get one encounter (I bought a nice upgrade for my sword from him).
There is an amulet at the bottom of the catacombs in Aleroth. I used it for the rest of the game, though if I hadn't put a gold strength charm in it (random drop by an opponent Zandalor kills) in order to equip a sword (dropped by someone near Stormfist Castle) I probably would have replaced it with the amulet from the Holy Item Quest late in the game. There is also an amulet in the cursed abbey (best to be in the late teens or early twenties for character level) and one in Stormfist Castle (may want to leave until you finish off the majority of Rivertown, including the sewers, and Verdistis... some people also recommend exploring part of the Dark Forest first).
One of the two soldiers you can heal in Aleroth will give you a ring when you reach Verdistis. Another ring can be found in a house north of the cursed abbey. I used these two rings until the end of the game.
As always, stats on items consistently in the game are still random. I saved before looting, or checking my inventory for the ring in Verdistis, then reloaded a few times to get good stats, saving if I found something decent but wanted to reload again (for items placed directly in your inventory, you need to move them in your inventory to set their stats, not just identify them).