Well, you have a free video editor built in to windows. It is called 'Windows Movie Maker' under (Start.programs, accessories) It takes a bit of getting used to but does fairly simple things.
The light settings on a video camera should be good enough to take scenes in-doors without added lights.
If not there may be a fault in the camera.
I have used a little Sony and never had problems with light. Everything is automatic and records in much darker surroundings than the DCLR camera.
Which Camera??? That is not something that can be answered just like that.
It will depend on what you are intending to take photo's of and what you wish to achieve.
It is rather like saying I am an artist...what sort of brushes and paints should I get.
So you have to tell us more. Have you any photo samples of the sort of thing you take pictures of?