"City Of The Daleks" is a PC Game which you can download on the official Doctor Who website. It was written by Phil Ford and was released on 5th June 2010.
Amy persuades the Doctor to take her to 1963 so she can meet the Beatles but when they arrive they discover that Earth has been destroyed by the mighty Daleks. The Doctor and Amy encounter the worlds last human, Sylvia, who gets killed whilst helping the Doctor and Amy destroy a Dalek with a trap. When they escape the underground, they are surrounded by Daleks but luckily they are able to sneak past them and enter back into the TARDIS.
Amy starts to fade away because she never existed because the Earth ended before she ever lived. The Doctor realises the consequences and goes back in time a year before the Daleks destroyed Earth and arrive on the Dalek planet, Skaro. There the Doctor finds a machine that helps Amy live longer and from there they get caught by the Daleks and are taken to the emperor