Emergancy request - someone with photoshop skills

[Combat squirrel]

Hi all, im trying my best to remove the people in the background in this shot :

I can balance the levels and other bits (which isnt dont in the shot yet) but iv been trying for hours to remove the people using various techniques such as clone stamp and placeing a different background in etc, but non realy work , if an ocuk photoshop expert could sort out the shot, remove the people, balance it and make it look awesome id be eternally grateful !

The Full size origonal untouched shot is here:

http://www.athp56.dsl.pipex.com/IMG_2820.JPG

Also whats the biggest print size you can print with a shot 3456 x 2304 (8MP) ? A3, A2 ? its not for this shot, its for a different picture I want to print and frame.

Any help would be awesomeness

 

[Combat squirrel]

wooow guys thats awesome, how on earth did u edit that out? mine looked all wrong!

 

[Combat squirrel]

Just want to say thanks to everyone that helped me out, great community and im very grateful ! just left with choosing which pic now, there both outstanding! , ill have a ponder over and then skoot to the printers later to get it printed off, surprise pressie for my other half thats in the pic!