Here's my two cents worth:
I would use Daz Studio.  I don't use it, but it will do a very competant job for what you want especially since you will have to  bring all of your rendered images into Photoshop and re-do everything the render did.

Poser is great, but it might be more than you need just to render a figure.

Vue is great, but it will contribute to your work only if you need atmospheres, vegetation, large vistas, cities etc.  For that, there is no better solution that is easier.  Plus, for poser figures, Poser and DS render those types of models better.

Photoshop CS 4 is great for all of your image editing.  the extended version is also good, but it doesn't necessarily replace the non extended one.  Even if you bring a figure into extended, retexture it, you will have to save it as a obj. model then load it back into poser or DS then assign the textures etc.  If you just use CS 4 and manipulate your texture maps, then all you have to do is save them and reassign to the model in Poser/ DS.  It might actually be quicker.  If you want the coolest tuts on Photoshop CS3/4 and extended, check out Planet Photoshop.  Those guys are top in their fields.

You say you have Poser Pro?  Stick with it.  It will render your characters better than VUE. 
I would render your figures in Poser and your backgrounds seperately.  Composite the images in Photoshop and blend them together.  I am presuming of course you are going for a "comic" book look.

I bet it took you years to become an accomplished writer, learning how to drive a story, introduce characters, build up a story behind them etc.  The same will go for your graphic skills.  Just be patient and give it some time to develope your style and talents with the software and it will come together.