Updated pics to show the new wheels and 'freshness' will help. If it were me I'd be looking at finding a second hand tailgate which isn't rusty, this will be putting people off - it shouldn't cost you much from a breakers yard.
However I think your biggest problem is that there are lots of MK4's for sale at the moment and it is a buyers market. Yours is pretty high mileage, and the 2.0 is not a desirable engine, if people are looking for performance then they go for the 1.8T (or another car all together), if they are looking for fuel economy then they go for a derv.
Pictures of the interior, engine bay and service history/paperwork may also help.