When I played I just scrambled whatever gear I could get and equipped it if it had a higher armour rating. I didn't worry too much about the weight of the armour early on, but if you have invested in the cat school or griffin school, then ideally you would try and stick to light armour or medium armour. But if you are looking for something specific, I found some good medium armour in Lindenvale atop a building, up a ladder. Don't know if it is the same every play through but you never know.
I found silver swords hard to come by, but if you can tackle some of the witcher contracts, then you can bag yourself a good one. Unfortunately they are quite difficult to begin with.
As you get further, you will definitely want to get hold of proper witcher armour as it is naturally stronger and you get good abilities with it as well.