I would recommend Photoshop Elements 6, which I use both at home and at work (for website graphics work, etc.). It costs around £60 in the UK. It can do all the Poser postwork you would ever need to do, and much more besides.

If you want to try a free 'equivalent' to Photoshop, there is The Gimp. I don't know it so I can't recommend it.

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)