Rust spot on bonnet

I know I'm bound to get some stick for saying that I've only just noticed this but I have :-)

I'm assuming that the whole bonnet will have to be resprayed but if anyone could hazard a guess as to cost, I'd appreciate it. It's on a 52-plate Nissan Maxima QX in case that makes a difference - like Nissan paints costing twice as much as others for instance :-)

TIA