You'll need something like Sony Vegas to do what you want, although if you really need to do the whole 'menu' thing with Blu-ray, rather than just burn the edited file directly from the timeline, then you're going to need the 'pro' version. Sadly, that's a
lot more money!
Here's a comparison between the various Vegas options
Sony Creative Software - Vegas Pro 9 - Vegas Family Comparison
Edit: There are other programs I should have mentioned, that have most of the Blu-ray writing facilities of the Vegas Pro package, but are a lot less money. You might check out Corel Videostudio, or Nerovison.
Probably worth a quick google to check that they work OK with Sony AVCHD.
In the early days of AVCHD, the different 'flavours' from the different camera manufacturers meant that that were some editing program compatibility problems. (Panasonic AVCHD wouldn't work with Vegas, for example), but I think that's all been resolved now.