When it comes to video there is no such thing as a stupid question - so don't worry. Up front I must be clear that I don't own this particular model, however:
All(?) AVCHD recording video cameras use derivatives of the MPEG 4 standard - so most modern editing packages will edit output from most video cameras. (Panasonic & Sony wrote the AVCHD standard) The exeptions are where someone has taken a lead and incorporated features that are brand new or unique to that manufacturer.
Each manufacturer has different interfacing software to allow the download from their camera to a pc. It is generally a very good idea to use it.
This software will provide (very) basic editing capability. So no matter what camera you buy you can at least carry out a basic edit.
Before we go any further the next problem you will hit in producing a high definition masterpiece is processor power - rendering an HD video uses all the power you can find. So before you invest in any software make sure that your computer meets the recommendations of the software manufacturer. I use a quad core processor and it is still slow.
I have a version (not the latest) of Windows Movie Maker and it wont touch my Panasonic AVCHD files with a bargepole.
I have just downloaded an AVCHD (1080i) file from a Panny HDC- TM700 and edited it in an old copy of Serif Movie Plus - so any modern editor will cope. When I got the camera, editing the enhanced 1080P format was a problem as it was brand new - however I don't need it and havn't tried it on a modern editor.
My guess is that your definition of decent editing software needs refining and that will involve time reading reviews on the internet as I am not brave enough to commit myself (I have tried most) - what some like others hate. It is all very different to still photo editing but I use the Serif SW a lot as it is fuss free.
http://video-editing-software-review.toptenreviews.com/ is one of many reviews.
As I have mentioned elsewhere I now mainly use Sony video kit as I find it more intuitive (and it used to have IR capability), but Panasonic is meant to have the quality edge - so I guess its what meets your needs best.
Sorry for the length of this.
Best of luck - J