Also I heard that a scope more powerful than 2-7x32mm would be overkill, is this true?
Maybe a bit! A 3-9x40mm would possibly look a little large on that rifle. There are other $100 scopes out there that would be great on this rifle. I only suggested the Vortex because I have heard that its a decent scope for that amount. I agree that the 2-7x32mm size would be perfect.
Here are two more in the size/price that you prefer:
If it were mine I'd put a Nikon ProStaff 2-7x32mm on it. Possibly a Redfield 2-7x33mm. Those are in the $140 price range, and well worth it.