Well i haven't seen the model but i have seen the texture you plan to use. its from filter forge and im fairly sure you cannot use there textures.
as far as i understand you want an organic alien ship right? much like the aliens in crisis.
that would take a lot of work. even if its just the exterior that you want. i suggest 4 options.
1 pay a fpsc modeler to do it for you
2 learn how to model and do it yourself
3 look up turbo squid and look for something suitable there. and lastly
4 make your own textures and don't Google search for em.
good luck with your model.
http://sites.google.com/site/jordanz2010/