Seems like a plot/script/whatever error.
It would have been funny if they didn't have FTL capabilities. BUT THEY DO. SO IT WASN'T. It was just STOOPID.
Edit: DUH. Buddha-X (in the comments) reminded me... DUH. It's going to take exactly a year for the light from the bomb's explosion to travel a light-year. (the bomb being the thing that alerted the cylon's to their location.)