Will ND filter help to prevent light sources from burning the image?
imagine nd filter as a piece of dark glass, it just dim the whole scene down, so to achieve correctly expose photo, u need to either increase exposure time or open aperture or increase iso or use combination of the above. so, by the time the buildings is correctly exposed, the street lamp will still be blown.
photography makes one sees things from all angles.
nd filter will help you sit there for 30 minutes while you do the exposure .
need exposure blending, hdr.. gnd won't really help properly here.
or if u wan to try for fun, then just take 3 shots 2 stops apart.. then feed them to your hdr software ...
I use gimp too, but there seems to be freeware out there for HDR (haven't tried).