
Quick and dirty in Graphics gale: I shrunk the image to 320x200 then applied mosaic filter.
It needs tidying up though.
Personally I would trace over the shrunken image in art software degined for pixel artists (such as Graphics Gale) using the line tool.
I did this with a photograph of a kitchen in Summer Woes.
Your best bet is to post in the critic's lounge, the guys that hang around in there are brilliant.