I'd go for the best second hand springer and scope combo you can aford. I know there a bit heavier but you'll learn to shoot better.
maybe a HK97 or a Air Arms tx 200.
Regards how many fills per bottle, try this web site matey.
Airgun HQ Tools
By the way I use a pump on my S200 and it's not that hard. That said the air from a bottle is of better quality.
Regards the AA S200. I've knocked over a F.T target at 55 yards with mine (11.5 ft lb .22) so I would say a kill is perfectly feasable. Would be a good shot though.