Can I get an rendered image more than 1024px large?

Hi,

I'm have to get an hight resolution image (I need at least a png or jpg - 36 inches large) and the only way I found is to use the rendering in Dimension...  not able to use the export setting in the file menu.

When I do a rendering to create a photoshop (or png) document, I'm always stuck with an image that have only 1024 dpi max even if I change the property of my canvas, i.e. in my case 10000 px large (12,5 inches), 800dpi. (not able to give more than 10 000 px large BTW).

in photoshop:

If I ask for more dpi, it still stays at 1024 dpi at the end.... just smaller size image in inches...

I will never get enough for my 36 inches image....

so...

Please help!

Thanks

/Ann