Ok, the evidence from the film strongly suggests that the Enterprise's journey from Earth to Vulcan took no more than an hour or two (This issue has already been discussed elsewhere). Then, after destroying Vulcan, the Narada warps off towards Earth, but there is another big discrepancy here as it appears to take the Narada far longer to reach Earth than it did for the Enterprise to travel the same distance. Think about it: After the Narada warps off, Kirk is cast off on Delta Vega, the Enterprise warps off to the Laurentian sector, Kirk wanders around on Delta Vega for an indeterminate period of time before miraculously running into Spock Prime, who then explains to Kirk in detail how he has come to be there, then they travel to the Starfleet base and meet Scotty, beam across space to the Enterprise, which then reverses its course to go after Nero. I'm not sure precisely how long all this would take, but it would have to be significantly more than just one or two hours, and the Narada is still travelling in this time. Logically, by the time the Enterprise reached the Sol system, Nero would already have blown Earth away.