I believe you can find Japanese wines in shops in Kyoto station, department store’s wine section and discount shops(such As DonQuijote). But if you want to hear and decide what to buy, you might want to go to liquor or wine shops. So here are some shops info I’ve found:
Not too far from Kyoto station, definitely wine shop.
How to get there on Google map;
-Liquor Burn Gion;
Located in Gion, so it might be convenient to stop by. They has English website.
Bit far from your stay and Kyoto station. But definitely wine shop, and they have nice list of Japanese wines.